[Reprinted from the Journal of the American Chemical Society, 96,2829 (1974).]
Copyright 1974by the American Chemical Soeiety and reprinted by permission of the copyright owner.
Copper(I) Alkoxides. Synthesis,Reactions,and
Thermal Decompositionl
George M. Whitesides,* John S. Sadowskioand Jennifer Lilburn
C o n tri b u ti o n fro mtheD epartmentofC herni stryl .| 14,,' sochuse| tsl nsti tuteo. f
Technology,Cambriclge,Massachusetts 02139. ReceiuedNouember17, 1973
betweenalcohols
Abstract: Alkoxides and phenoxides of copper(I) can be prepared by the heterogencousreaction
for the formation of
and phenols and methylcopper(I). These organocopper(I) compounds are useful reagents
aryl halidesyields
ethersby displacementof haiide from organic halides. The reaction of copper(l) alkoxidcswith
reagcnts
alkyl aryl ethersunder particularly mild ionditions. Thermal decompositionof primary alkorycopper(l)
reagents
alkoxycopper(l)
secondary
of
clecomposition
Thermal
generates intermediate alkoxy radicals.
to involve
apparently can take place either by a free-radicalmechanismor by a mechanismtentatively suggested
for
predominate
will
mechanism
which
determining
factors
copper(I)-hydrideas an intermediate. The structural
a given compound have not been established'
tTth. utitity of alkyl- and arylcopper(l) reagents in
I or ganic s y nt h e s i si s b a s e d o n th e i r h i g h nucl eop h i l ic it y t owar d c a rb o n , a n d o n th e i r a b i l i ty to take
part in electron-transferreactions.2-a They also show
low basicity toward protons, an afffinity for carbonca rbon double bon d s , a n d a n a b i l i ty to c o o rd i n atew i th
soft Lewis bases. Since the mechanisms by which
copper(I) influences the reactivity of carbanions are
not clearly understood, it is difficult to predict the beh a v ior of new t y p e s o f o rg a n o c o p p e r(I)c o mpounds.
Nevertheless,there is obvious reason to hope that
organic derivatives of copper(I) other than those bel o nging t o t he we l l -e x p l o re dc l a s s o f c o mp o u nds containing carbon-copper bonds might also show useful
( 1 ) S u p p o r t e d b y t h e N a t i o n a l S c i e n c eF o u n d a t i o r l , G r a n t s G P 28586X ancl GP-14247, ancl by the International coppcr Rcsearch
Association.
( 2 ) J . F . N o r m a n t , S ) ' n t h e s i s , 2 , 6 (31 9 7 2 ) ; G ' H . P o s n e r ,O r g ' R e a c t ' ,
19, | (1972),
( 3 ) G . B r i h r a n c l P . B u r b a i n " M e t h o d e n d e r o r g a n i s c h e nc h e m i e "
( H o u b e n - W e y l ) ,V o l . X I I I / 1 , E ' M i , i l l e r , E d . , G e o r g T h i c m e V c r l a g ,
S t u t t g a r t ,1 9 7 0 ,p 7 3 1 f f .
( 4 ) O . A . C h a l t y k i a n , " C o p p e r - C a t a l y t i cR e a c t i o n s , "A . E . S t u b b s ,
t r a n s . , C o n s u l t a n t sB u r e a u , N e w Y o r k , N ' Y . , 1 9 6 6 ; P . F . F a n t a ,
C h e m . R e c , , 6 4 , 6 1 3( 1 9 6 4 ) ; R . G . R . B a c o n a n d H . A . O . H i l l ' Q u a r t '
, . A i s e n ,a n d W . E ' B l u r n R e c . ,C h e m .S o c . ,1 9 , 9 5 ( 1 9 6 5 ) ; J . P e i s a c h P
berg, Ed., "The Biochemistry of Copper," Academic Press,New York,
N. Y.. 1966.
reacti vi ty. Thi s paper descri besstudi es of o ne such
cl ass: al koxi desof copper(l ). Thesestudi eshad t hr ee
obj ecti i es: synthesi sand characteri zati onof alkoxides
u n d p h e n o x i d e so f c o p p e r ( l ) ; d e t e r m i n a t i o no f t h e
i n reacti onsw hose usef ulbeharl i orof thescsubstances
ness w i th al kyl copper reagentshas al ready b een establ i shed: and exami nati onof the mechani smsof t heir
thermaldecomposi ti on.
C opper(l ) al koxi des and phenoxi deshave been im pl i cated previ ousl y as i ntermedi atesi n a var iet y of
reacti ons,a'and
5 poorl y chara ct er ized
copper-catal yzed
exampl esof thesesubstanceshave been prepa r ed'6 A
useful synthesisof copper([) tert-butoxideTis not appl i cabl e to the preparati on of the thermal l y u nst able
wer e
copper(I)
^centralpri mary and secondaryal koxi des th at
i nterest i n our w ork. The prepar at ion of
of
copper(I) phenoxi deby a procedureanal ogou st o t hat
descri bedhere has beenreported.s C opper(I)a lkoxides
(5) J. K. I(ochi, Proc. Ittt. Congr.Pure Appl' Chem', 23rd,4' 377
(1971),and referenccscitcd therein,
( 6 ) b . E . H . B a w r ra n d F . J . W h i t b v , J . C h e m . 9 o c . , 3 9 2 6( 1 9 6 0 ) ; G '
C o s t a . A . C a m u s , a n d N . M a r s i c h , J . I n o r g ' l ' ' l u c l 'C h e m ' , 2 7 ' 2 8 1
(Ie6s).
( 7 ) T . S a e g u s aT, . T s u c l a ,a n d T . H a s h i r n o t o ,J ' A m e r ' C h e m ' S o c "
9 4 , 6 5 8( 1 9 7 2 ) .
45, 1499
iSl f. I(awaki and H. Hashimoto, Bull. Chem. Soc' Jap',
(r972).
Whitesides,et al, I St'nthesisttf Cttpper(l) Alkoxides
2830
h a v e been s ugge s te da s " h o l d i n g g ro u p s " i n mi xed
, e t(R )C u L i .' $
co pperat e c om ple x e sH
Results
and Characterizationof Copper(I) Alkoxides
S1'nthesis
and Phenoxides. Copper(t) alkoxides were obtainecl
by heterogeneousreaction between dry, oxygen-free
a l co holsand halid e -fre eme th y l c o p p e r(I)a t 0 o u nder a
nitrogen atr-nosphere(eq l). With the exception of
(CH3Li)r *
4"(Bu.zS).zCu["---->
(c H :,c u ),t
*h
" R o C u " + c Hl t
(l )
co p per ( l) m et hoxi d e , th e c o p p e r(l ) a l k o x i d e s w ere
so l uble in et her a t 0 o ; m o s t w e re a l s o s o l u b l e i n hyd ro c ar bon s olv en ts .a l th o u g h c o p p e r(I) c y c l o h exoxi de
a n d c y c lopent oxi d ep ro v i d e n o ta b l e e x c e p ti ons(ci de
infra). Copper(l) alkoxides were precipitated from
e th er s olut ions as l i g h t y e l l o w s o l i d s o n c o o l i ng to
-7 8" , and wer e p u ri fi e d b y w a s h i n g w i th c o l d ether.
Co p per ( l) m et hox i d e a n d c o p p e r(l ) p h e n o x i d esw ere
o b tainedus inga si m i l a r re a c ti o n ; h o w e v e r,s i n cethese
su b s t anc esar e inso l u b l e i n e th e r. th e i r fo rm a t i on w as
h e ter ogeneoust hro u g h o u t. T h i s p ro c e d u re for the
p re par at ion of c o p p e r(l ) a l k o x i d e s i s a re asonabl y
g e ner alone. alt ho u g h h i g h mo l e c u l a r w e i g h t a l cohol s
so met im esr eac t s l o w l y o r i n c o mp l e te l yw i th methyl co p per ( I ) . F ur t h e r, th e i s o l a te d y i e l d s o f c o pper(l )
a l ko x idesar e m ore v a ri a b l eth a n o n e w o u l d l i k e (ui de
i n .fr u) . V igor ous a g i ta ti o n o f th e s u s p e n s i o no f methyl co p per ( l) in t he s o l u ti o n o f e x c e s sa l c o h o l i n ether i s
re quir ed t o ac hie v eh i g h y i e l d s o f c o p p e r(l ) a l k oxi des.
Si m ilar pr oc edure s h a v e b e e n a p p l i e d to th e synth es is of c opper ( l ) c a rb o x y l a te s ,a n d s e e m to w ork
smoot hly .
Copper ( I ) alk ox i d e sa re h y d ro l y z e d o n c o n tact w i th
w a ter and r apid l y o x i d i z e d b y a i r. T h e i r thermal
sta bilit y dependso n th e i r s tru c tu re : c o p p e r(l ) deri vati ves of t er t iar y a l c o h o l s a re s ta b l e fo r h o u rs at temp e r at ur esles s t ha n 1 7 0 o , w h i l e th o s e o f p ri m ary al co hols dec om pos era p i d l y a t ro o m te mp e ra ture. The
se ns it iv it yof m any o f th e s ec o m p o u n d sp re c l u d edcomb u s t ion analy s isa s a me th o d o f e s ta b l i s h i n ge m pi ri cal
co mpos it ion. I nste a d ,s a m p l e sw e re h y d ro l y zed.and
th e r at io of alk ox y to c o p p e r m o i e ti e s(R : R O/C u) i n
th es es am pleswasd e te rmi n e d . T h e s ea n a l y s e isn di cated
valuesof R in satisfactoryagreementwith the expected
v a l u e R : 1 . 0 : f o r c o p p e r ( l ) m e t h o x i d e ,R : 1 . 0 6 :
fo r c opper ( l) n- bu to x i d e ,R : 0 .9 8 : fo r c o p p er(I)rertb u tox ide,R : 1. 0 4 ; fo r c o p p e r(l ) c y c l o h e x o x i de,R :
1 . 0 4 ; f o r c o p p e r ( l ) i s o p r o p o x i d e ,R : 1 . 0 1 . T h e s e
re s ult sleav eno do u b t th a t th e m a te ri a l so b ta i n edusi ng
th e pr oc edur eout li n e di n e q I a re c o p p e r(l )a l k o xi des.
For c er t ain s y n th e ti c a p p l i c a ti o n s ,i t p ro vecl conve nientt o us e an a l te rn a ti v ep ro c e d u refo r th e preparation of copper(l) alkoxides. Reaction of lithium
a l kox ide wit h a su s p e n s i o no f c o p p e r(l ) c h l ori de i n
d i m et hox y et hanea t 0 o re s u l te d i n fo rm a ti on of a
h o mogeneous s o l u ti o n c o n ta i n i n g o rg a n o metal l i c
sp ec ieswhos e r ea c ti v i ty w a s e s s e n ti a l l yi n d i s ti ngui sha b le f r om t hat of p u re c o p p e r(I) a l k o x i d e s . The obse r v at ion t hat c o o l i n g th e s e s o l u ti o n s d i d n o t resul t
i n pr ec ipit at ion o f c o p p e r(l ) a l k o x i d e s s u g g e stedthat
(9) G. H. PosrrcrC
, . E . W h i t t c n , a t r d J . J . S t c r l i n g ,J . A m c r . C h e n t .
S o c . ,9 5 , 7 7 8 8( 1 9 7 3 ) ; s e ea l s o W . H . M a r - r d e v i l lacn c lG . M . W h i t c s i d c s ,
J . O r g . C h e n r . , 3 9 , 4 0(01 9 7 4 ) .
Journol o/'tlte Antericun Clrcnticol Societt' I 96.9 I Mu.r I, 1971
l i thi um chl ori de w as compl exed w i th organ ocopper
speci espresenti n sol uti on. and no seri ouseffo r t s wer e
made to i sol atc pure copper(l ) al koxi des fron r t hese
sol uti ons. N everthel ess.si nce al kal i metal alkoxides
a r e f r e q u e n t l ym o r c r e a d i l y o b t a i n e di n l a r g e q u a n t i t y
, i s p r o c e d u r ew i l l b e t h e m o r e
t h a n i s m e t h y l c o p p e r ( l )t h
conveni entfor the preparati onof w hat are presum ed.
on the basi sof reacti vi ty,to be copper(l ) sal ts of t hese
al koxi des,at l east for practi cal appl i cati onsi nvolving
l arge quanti ti esof these materi al s.
Oxidation of Copper(I) Alkoxides. The dimerizatiort
of organi c groups by oxi dati vecoupl i ng of the or ganic
seem s
moi eti esof copper(l )al kyl s, aryl s,and acetyl en es
to have no anal ogy i n the chemi stry of copper ( l)
al koxi des: reacti on w i th rnol ecul ar oxygen occur s
s m o o t h l y , b u t i r i e l d so n l y c o p p e r ( l l ) a l k o x i d e s : r e a c t i o n o f c o p p e r ( l ) n - b u t o x i d ew i t h n i t r o b e n z e n ey i e l d s
r i - b u t a n ailn 2 2 1 , ;y i e l d .
Reactionsof Copper(I) Alkoxides and Phenoxideswith
Organi c H al i des. C oupl i ng of organi c groups by
nucl eophi l i cdi spl acementof hal i dei on from an or ganic
hal i de by the al kyl moi ety oi a l i thi unr cl i al ky lct r pr at c
i s one of the most useful rcacti ttnsof orgi ttto copper ( l)
c o m p o u n d s . : A n a l o g o u s n u c l e o p h i l i cr e i t c t i o t l sb c t w e e n a l k y l h a l i d c sa n d c o p p e r ( l ) a l k o x i c l e sp. r c p r r r e t l
a c c o r d i n g t o e q l . g i v e m o d e r a t e y i e l d s o f t l i r r l k rI
e t h e r s( T a b l c I ) . r " T h c s ey i e l d sr e s p o n ctl o c h l r l g e\ i n
Table I.
R e a c t i o n so f C o D n e r ( l ) A l k o x i d e s w i t h A l k r l H a l i d c r
ROM
rr-CrHlOCu
R'X
l-C,HrBr
Solvent
T e n r p .R O R
(
Et:O
EtJO-H M PA
Digli,me
l(x)
P;,ridine
,scc-CrH,,OCu
lerl-CrHlOCu
CoHiOCr-r
n-CrHlCl
rl-CrHll
l-CrH,,OTs
.ter'-CrHlBr
lcrl-C rHrrBr
Bromocyclohexarre
(cH,,)rccHzBr
n-CrHrBr
rl-C+Hr,l
rl-CrHlBr
l-5
ll5
l-5
--.1
5-5
55
53
100
6)t'
n-C+HgOLi
rl-CrHlBr
P1'ridine
EtIO_H M PA
75"
" T h e s t a r t i t i g c o r r c e n t r a t i o no f R O C u w a s a p p r o x i m a t c l l 0 ' 2 N "
R ' X w a s p r e s e n t i n 5 0 ' 1 , ,e x c e s s . A l l r e a c t i o n s w e r e a l l o w e c i t o
proceeclfor 1.1lrr at tlre temperature indicated. Ytelds were determ i n e < l b y ' g l p c . a n c l a r e b a s e d o n t h e a s s u m p t i o r tt h a t t h e f i e l c l o f
c o p p e r ( l ) a l k o x i d e i s o l a t e c ll ' r o m r e a c t i o n o f r l e t h y l c o p p e r ( l ) w i t h
nl this point.
a l c o h o l w a s 6 4 . 5 0 ' ), , . T h e t e x t c o n t a i n sa c l i s c u s s i o o
/ ' I s o l a t e c ly i e l d L r a s e do n m e t h y ' l l i t h i u m . ' Y i e l c l s w e r e d e t e r m i n e d
b y g l p c . a n c l . t o m a k e c o n t l - r a r i s o nw i t h t h e c o r r e s p o n d i n g y i e l d s
f r o m t h e c o p p e r ( l ) a l k o x i c i e sp o s s i b l e .a r e r e p o r t e d o n t h e a s s u m p t i o n t h a t t h e I i e l c l o [ l i t h i r - r ma l k o x i c l e f r o m r e a c t i o n o f m e t h y l l i t h i u m r v i t h a l c o l . r o lw a s c r r . 5 0 1 i . I n r c a l i t y . t h i s y ' i e l di s p r o b a b l y
q u a n t i t a t i v e . s c l t h a t t h e t r u e y i e l d o f R O R ' l ' r a s e do n R O L i i s [ a l I
of that given.
( l 0 ) C o n v c u t i o n a ln r c t h o c l sf o r t h c p r c p a r a t i o no f a l k y l a r l d a r y l
c t h c r s a r c s l r r v c y c ctl r y C . A . B c u h l c r a n d D . E . P c a r s o l t ", S u r v c y o f
c ,c w Y o r k , N . Y . , 1 9 7 0 ,C h a l l O r g n n i c S l n t h c s c s , "W i l c l ' - l r t t c r s c i c t r cN
t c r 6 , a p c l l t 1 H . \ { c c r u c i r t i r t " M c t l . r o c l c tcl l c r O r g a r r i s c h c lC l . r c r . r r i c "
( H o u b c n - W c : l ) , V I 3 , E . \ ' t i . r l l c r ,E c l . ,G c o r g T l . r i c r u cV c r l a g , S t t r t t g a r t ,
1 9 6 5 ,p I l l ' .
2831
re a c t ionc ondit ion sa n d re a c ta n ts tru c tu re i n a fashi on
th a t is qualit at iv e l y s i m i l a r to th a t c h a ra c te ri zi ngthe
Wi l l iam s on et her s y n th e s i s : p ro d u c ti o n o f e thers i s
fa vo r ed by t he us e o f p y ri d i n e l t o r p o l a r a p roti c sol v e n t s : 1 1e l i m i n a t i o ni s a s e r i o u ss i d e r e a c t i o n i n d i s p l a c em ent sat s ec o n d a ryc e n te rs . T h e y i e l d s o f ethcrs
fo rm ed by r eac t io n o f c o p p e r(I) a l k o x i d e sa n d a l kyl -X
d e cr eas edin t he ord e r X : O T s > B r - t > Cl l the
co rres pondingor de r fo r a ry l -X w a s X : I ) B r )) OTs
> C l. T he r eac t i o n o f c o p p e r(l ) a l k o x i d e sw i th al kyl
s v e r th e Wi l l iamson
h a l i d es of f er s c er t a i n a d v ' a n ta g e o
syn t hes isof et her s i n th a t re a c ti o n c o n d i ti o n s i n the
fo rm er ar e m ilder th a n th o s e u s u a l l y e mp l o y e d i n thc
l a t t e r ,a n d e l i m i n a t i o na p p e a r st o b e a s m a l l e rp r o b l e m :
h o w ev er ,it s uf f er sf ro m th e d i s a d v a n ta g eth a t c o pper(l )
a l k o x i d e sa r e o r d i n a r i l yl e s sr e a d i l ya v a i l a b l ea n d m o r e
s e n s i t i v et o t e m p e r a t u r ea n d o x y g e n t h a n a r e a l k a l i
l n e tal alk ox ides .
The r eac t ion of c o p p e r(l ) a l k o x i d c sw i th a ry l hal i des
p ro d uc es alk y l ar yl e th e rs i n g o o d y i e l d s (T a b l e l l ).
Alkoxides
withAryl and
of Copper(l)
TableII. Reaction
VinylicHalides'
ROM/,
ll-C+HoOCu
ArX.
Phenyl p-toluenesulfonate
Iodobenzene
Solvent
Temp. ArOR,
oC
7"1
Pyridine
n-CrHrOLi
(10i.; CuCl)
n-C,rHoOCu"
sec-CrHgOCu
Iodobenzene
3-lodotoluene
4-lodotoluene
Bromobenzene
Iodobenzene
lerl-C.rHlOCu
CtH;OCu
rl-C.HrOCu
85
25
I l5
75
70
100
25
ll5
Chlorobenzene
Bromobenzene
Iodobenzene
Dimethoxy'ethaneHMI'A/
1-Bromocyclohexene
Pyridine
12
I
29
64
90
<t
6-s
98
96
Diglyme
Pyridine
l-CrHsOCu"
25
55,,
65',
45,,
85
86
96t,
94
85
a 1 ^
" The starting concentration of copper alkoxide was approxirnately 0.1 l/. Reactions were carried out for l2 hr. r Copper(l)
alkoxides were prepared by the reaction of methy'lcopper(l)with
the alcohol. unless otherwise noted. " A 501.. exce:is of the aryl
halide was employed. d Yields are determined by glpc based on
the copper(l) alkoxide. unless otherwise noted. " The copper(l)
alkoxide was prepared by the reaction of the lithium alkoxide with
cuprous chloride. / The DMF contained 4 equiv of HMPA/equiv
of lithium. o Isolated yield based on methyllithium. The ethers
produced in these reactions were isomericalll,' pure within the limits
I Copper(l) lerl-tlutoxide was
o f d e t e c t i o n o f t h e a n a l y s i s( + 5 % ) .
prepared by the reaction of potassium /e/'l-blltoxide with cuprous
chloride.
Wi th in t he lim it ed ra n g e o f re a c ti o n se x a m i n ed,comp a ra ble y ields of a l k y l a ry l e th e rs a re o b ta i n e d from
co p p er ( l) alk ox ide s p re p a re d a c c o rd i n gto e q 1, from
(11) Reaction of copper(I) carboxylates with alkyl halidcs occurs best
in pyridine: A. H. Lervin and N. L. Golclberg, Tetrahedrort Lctt.,491
(1972). Magncsiurn nlkoxicles rcact with alkyl halides in hcxarncthylp h o s p h o r a r n i d c t o g i v e c t h c r s i n g o o c l y i c l c l; Y . L c r o u x , M . L a r c h e v e q u e ,a n d J . - C . C o m b r c t , B u l l . S o c . C h i m . F r . , 3 2 5 8 ( 1 9 7 1 ) .
the speci es(or mi xture of speci es)obtai ned by react ion
o f l i t h i u m a l k o x i d e sw i t h c u p r o u s c h l o r i d c ,a n d f r o m
l i t h i u m a l k o x i d c i n t h e p r e s e n c eo f a p p r o x i m a t e l yl 0
mol 7,:, cuprousr2 chloride. Again. pyridine or
e t h e r e a ls o l v c n t sc o n t a i n i n g H M P A p r o v i d e t h c b e s t
r e a c t i o n m e d i a . H i g h e r t e m p e r a t u r e so r l o n g e r r e acti on ti mes ure requi red for these reacti onsth an f or
t h e r e a c t i o n so f c o p p e r a l k o x i d e sw i t h a l k y l - h a l i d e s ,
a l t h o u g ht h e s ed i s p l a c c m e n tdso t a k e p l a c ea t a s e r ri c e able rate even at room temperature. One important
functi on of pyri di ne i n thesereacti onsseemsto be t hat
o f s t a b i l i z i n gt h e c o p p e r a l k o x i d e s a g a i n s t t h e r m a l
d e c o m p o s i t i o n : 1 'i rt m a y a l s o c h a n g et h e r e a c t i v i t yo r
extent of aggregati onof the copper al koxi des by coordination.
These reacti onsprovi de the bcst avai l abl epro cedur e
f o r t h e c o n v e r s i o no f a r y l h a l l d e si n t o a r y l a l k y l e t h e r s .
A l ternati vc prepai ati ons based on reacti ons bet ween
p o t a s s i u ma l k o x i d e sa n d a r y l h a l i d e s r e q u i r e m o r e
vi gorouscondi ti onsand produce l ow er yi el ds of pr oducts, and i n addi ti on suffer from the possi bi lit y t hat
i n t e r v e n t i o no f a n a r y n e m e c h a n i s mi n a n y n e w e x a m p l e m a y l e a d e i t h e rt o a m i x t u r e o f p r o d u c t so r t o a
s i n g l ep r o d u c ti n w h i c h t h e p o s i t i o no f t h e e t h e rl i n k a g c
isambiguous.ra
Thermal Decomposition of Copper(l) Alkoxides.
T h e t h e r n r a l s t a b i l i t y o f c o p p e r ( l ) a l k o r i c l e si s a p p r e c i a b l yh i g h e r t h a n t h a t o f c o p p e r ( l ) a l k y l s : f o r
exampl e. on w armi ng tt-t roont temperattr r e f r ont
- 7 8 o . c o p p e r ( l ) n - b u t o x i d ei s s t a b l e f o r 1 2 h r . w h i l e
i r - b u t y l c o p p e r ( ld) e c o m p o s e isn 2 0 m i n . N o n e t h e l e s s .
t h e r m a l c l e c o n r p o s i t i o no f c o p p e r a l k o x i d e s i s a n
i m p o r t a n tc o m p e t i n gp r o c e s sw h e n r e a c t i o n so f c e r t a i n
o f t h e s e s u b s t a n c e sa r e c a r r i e d o u t a t t e m p e r a t u r e s
a b o v e a m b i e n t . a n c l i n f o r m a t i o n c o n c c r n i t t gt h e s c
t h e r m a l d e c o n r p o s i t i o niss p e r t i n e n tt o t h e i r s y n t h e t i c
application.
M a n y p a t h w ' a y se r i s t f o r t h e t h e r m a l d e c o m p o s i t i o n
o f t r a n s i t i o n n i e t a l o r g a n o n t e t a l l i cc o m p o t t n d s i n
g e n c r a l . l i - : r a n d o f o r g a n o c o p p e r ( l )c o m p o t t n d s i n
p a r t i c u l a r . r \ - r : A l t h o u g h i t h a s b e e n p o s s i b l et o d e f i n e c e r t a i n d e t a i l s o f t h e s ed e c o m p o s i t i o n si t. i s s t i l l
r,' erydi {Ii cul t to predi ct the processthat w i l l dom inat e
for a parti cul ar organometal l i crcagent. C om par ison
( 1 2 ) R . G . R . B a c o n a n d S . C . R o r n i s o t ' Jr ,. C h e m . . S o cC
. ,312
( 1 9 6 9 )h a v c n o t c d t h a t t h c n u c l c o y t l ' r i l i c iot yf ' s o c l i u r rar l k o r i c l c st o l v a r c l
l r r y l h a l i c l c si s i n c r c r t s c cbly t l i c p r c s c n c co f c o p l l c r s l l t s .
( 1 3 ) A s i m i l a r f t r n c t i o r ri s s c r v c db y t r i l r r y l l l h o s p h i r r c sh: o r v c v c ' rt,h c
p r c s c n c co l ' s t o i c h i o r r t c t r iqc u a t t t i t i c so f p h o s p h i l c s i n o r g a r l i cr c a c t i o n
m i x t u r c sc o n r p l i c a t ctsh c i r r v o r k - u p .
( 1 4 ) M . R . V . S a h y u tar t r c D
l . . 1 . C r a r l , O r g . S - r ' r r . , 4 5 , 8(91 9 6 5 ) l
J . S . B r a c l s h a wE. . Y . C h c n , R . H . H a l c s ,a r r t lJ . A . S o u t h ,. 1, O r s . C l t e t r t . ,
3 ' 7 . 2 0 5 1( 1 9 7 2 ) : D . J . C r a n r , B . R i c k t r o r r r r, t t . t cGl . R . I ( r r o x , J . ' 4 m e r .
Chent.Soc.,82. 6412 (l 960\.
( 1 - 5 )P . S . B r a t c r n r a r a
t n c lR . J . C r o s s ,J . C h e m . S o c . , D a l t o r tT r a t t s ' ,
6 , \ 7( 9 7 2 ) .
( 1 6 ) G . M . W h i t c s i d c s , . lF. . G a a s c h a, n c lE . R . S t c c l r o r l s k y., .Al n t e r .
, . B c r g b r c i t c r ,l r t c l
C h c r n .S o c . , 9 4 , 5 2 - 5 8( 1 9 7 2 ) ; G . M . W h i t c s i c i e sD
P . E . I ( c r r c l a l li,b i d . , 9 6 ,2 8 0 6( 1 9 7 1 ) .
t . r g c u t o m e t aC
l.hem',
( 1 7 ) G . W . P a r s h a l la n d J . . 1 . M r o r v c a , A c l L ' a rO
7 , 1 s 7( 1 9 6 8 ) .
( 1 8 ) G . M . W h i t c s i d c sC
, . P . C a s c y ,a n d J . I ( . I ( r i c g c r , J . A m e r . C h e m .
S o c . ,9 3 , 1 3 7 9( 1 9 7 1 ) .
( 1 9 ) A . C a i r n c r o s sa r t c lW . A . S h e p l r a r t l',1 . A n t e r . C h e m . S o c . , 9 0 ,
2 1 8 6 ( l c ) 6 8 ) ; 9 3 , 2 4 7 ( 1 9 7 1 ) : A . C a i r r r c r o s sH, . O t r r u r a ,a n c l W . A .
S h c l r p a r di ,b i d . ,9 3 . 2 4 8( 1 9 7 1) .
( 2 0 ) M . T a t r u n t a r r c l. 1 . l ( . I ( o c h i , J . O r g a t r c m e t a lC
. h e m , ,4 2 ' 2 0 5
(1e72).
( 2 1 ) G . M . W h i t c s i c l c sE, . J . P a n e k ,a n c lE . R . S t c c l r o n s k yJ, . A m e r .
Che m . S o c . ,9 4 , 2 3 2( 1 9 72 \ .
( 2 2 ) C . M . W h i t c s i d c s ,E . R . S t e c l r o n s k yC, . P . C a s c y ,a n d J ' S a n
F i l i p p o , J r . ,J . A m a r . C h e m .9 o c . , 9 2 , 1 4 2 6( 1 9 7 0 ) '
Whitcsides,et al. I St'nthesisof Copper(l) Alkoxides
2832
of the mechanism(s)of thermal decomposition of corre spondingc oppe r(I) a l k y l s a n d a l k o x i d e ss h o ul d hel p
to define the factors that determine the dominant decompositionpathways.
The major products of the thermal decomposition
o f pr im ar y and s e c o n d a ry c o p p e r(l ) a l k o x i d es are
co p per m et al, alc o h o l , a n d th e k e to n e o r a l dehyde
formally derived from oxidation of the alcohol (eq 2).
(2)
RCH:OCu----> RCH:OH 1 RCH-O a Cu(O)
Solvent Effects on the Distribution of Products from
Table III.
tl.reThermal Decomposition of Copper(i) Alkoxides"
Two fundamentally different types of mechanismswere
considered in trying to account for these products.
b y e q 3 a n d 4 , i n v o l v e sa n i n i tial el i mOn e , r epr es ent ed
----> RCH:O 1 CuH
(3)
RCHTOCu
RCHTOCu
f CuH ----> RCHzOH1 2Cu(O)
(4)
i n a t ion of c opp e r(t) h y d ri d e fro m o n e c o pper(l )
alkoxide moiety, followed by reduction of a second
co pper ( l) alk ox id e b y th i s c o p p e r(l ) h y d ri d e . Thi s
me c hanis mhas be e n e s ta b l i s h e dfo r th e d e c o m posi ti on
n- but y l( t r i- n -b u ty l p h o s p h i n e )c o p p e,2
r(l0)- 22 but
of
cl e ar ly c annot be i mp o rta n t i n th e th e rma l decomp o sit ion of , €. g., c o p p e r(l ) l c rl -b u to x i d e , fo r w hi ch
vi cinal c opper ( t ) h y d ri d e e l i m i n a ti o n i s i m p ossi bl e.
Th e s ec ondm ec ha n i s m(e q 5 a n d 6 ) re q u i re sh o mol yti c
----> RCH:O' * Cu(O)
(5)
RCHTOCu
--->
(6)
products
RCHTO.
scission of a copper-oxygen bond, followed by gene ra t ion of pr oduc ts fro m th e i n i ti a l l y fo rme d al koxy
ra dic als : t his m e c h a n i s m w o u l d a l s o b e a ppl i cabl e
to t he dec om po s i ti o n o f l c rl -a l k o x y c o p p e r (l ) comp o unds . B y way o f p re c e d e n t,th e rma l d e c o mposi ti on
u i a f r ee alk y l r adi c a l s i s o f e s ta b l i s h e di m p o rta ncefor
co pper ( t )alk y ls c o n ta i n i n gn o h y d ro g e na to m s p to the
ca r bon- c opper bo n d .2 1 T h u s , a p ro b l e m o f central
c o n c e r n i n d e t e r m i n i n gt h e m e c h a n i s mo f t h e r m a l
d e c om pos it ionof a c o p p e r(l ) a l k o x i d e i s th a t of dete rm ining whet he r c o p p e r(l ) h y d ri d e o r fre e al koxy
ra dic alsar e int er me d i a te si n th e d e c o mp o s i ti o n .2' r
Our f ir s t appr o a c h to th i s p ro b l e m c e n te red on i l
stu dy of t he inf lue n c eo f s o l v e n t o n th e d i s tri b uti on of
p roduc t sf r om t he th e rma l d e c o m p o s i ti o no f re p resentati ve c opper ( l) alk o x i d e s (T a b l e III). If fre e al koxy
ra d ic als ar e int e rm e d i a te si n th e s e th e rma l decomp o sit ions ,t hen t h e y i e l d o f a l c o h o l p ro d u c e d rel ati ve
to t hat of t he c a rb o n y l -c o n ta i n i n gp ro d u c t s h oul d be
h i g her in s olv ent sth a t a re m o re a c ti v eh y d ro g endonors
to war d alk ox y r a d i c a l s th a n i n th o s e th a t are l ess
a ctiv e. 2a T he c o p p e r(l ) a l k o x i d e s e x a m i n e d f el l i nto
tw o c at egor ies : th o s e (u .g ., c o p p e r(l ) rl -h eptoxi de,
cyclohexoxide,and cyclopentoxide)for which the ratio
(23) A numbcr of variants are conccivable for a free-radical cleconlposition. At orrc cxtrcmc, initial clccomposition of the copper(l)
alkoxidc could yield a clialkyl pcroxide, which woulcl clecorrposc' in a
subsequent stcp to frcc alkoxy radicals. As prcccdent, dccompositiorr
of vinylic and aronratic orgauocoppcr(l) cotlpouncls producc orgltrtic
d i m e r s i n a r e a c t i o n t h a t c l o c sn o t i n v o l v e f r c e - r a d i c a l i u t e r m c c l i a t e s . t r ' i g
Alternativcly, nlkoxy radicals gcncrated by hornolytic scission of a
carbon-coppcr bond might attack copper(I) alkoxidc to incluce radical
Regarcllcss, the most irlrr.recliate rlcchatristic clistinctiorr
forrnation.
to bc made is that betrveen thosc rcaction schemcs that involvc ittterrnediate frcc alkoxy radicals, and those that do not.
( 2 4 ) T h e h y d r o g c n a t o r n c l o n o r a b i l i t i e s l i s t e d f o r t h c s o l v c n t s u s e c li n
Table III are those estin.ratccl olt a per molecule basis fror.r.rclata for
r e a c t i o n s o f / e r l - b u t o x y r a c l i c a l sr v i t h t h c s c s u b s t a n c e s : c / . W . A . P r y o r ,
"Free Radicals," McGraw-Hill, Ncw York, N. Y., 1966: C. Walling,
Pure Appl. Chem.,l5. 69 (1961): A. L. Willianrs, E. A. Obcrright, and
J. W. Brooks, J. Amer. Chem. Soc., 78, 1190 (1956); J. A. Hor.varcl,
Adcan. Free Rqclicctl Chem., 4, 49 (1972).
Journal o/'the Anterican Chemical Society I 96:9 I May l, 1974
ROCU
Solvent (H
donor ability)b
Toluene( I .0)
I ) e n t a n(e2 . 6 )
THF (23)
(0.0004)
Copper( I) cyclohexoxic'le Benzene
C u m e n e( 2 . 5 )
P e n t a n (e2 . 6 )
THF (23)
C o p p e r ( l ) c y c l o p e n t o x i d e P e n t a n (e2 . 6 )
THF (23)
P e n t a n (e2 . 6 )
CH3CH(OCu)C;Hz
THF (23)
Benzene(0.0C[4)"
CTHiCH(OCu)CzH;
T e t r a l i n( 4 . 3 ) "
Ether(23)i
Toluene(l .0)
C6H,rCH(OCr-r)CoH;
P e n t a n (e2 . 6 )
THF (2])
C o p p e r ( I ) c y c l o b u t o x i d e P e n t a n (e2 . 6 )
THF (23)
rr-CzHr;,OCu
Product
Alcoholi balance,
carbonyl'
%
3.1
2.9
r0
1 04
2 7t,
2.32
873
l. lB
768
o74
0.89
0.96
0.79
r.83
l.r9
0.12
I .39
0.80
0.80
92
79
88
100
9r
86
84
72
89
83
90
r00
86
80
72
72
,, The decompositions were carried out by heating solutions
o r i g i n a l l y0 . 3 + O . l M i n c o p p e r ( l ) a l k o x i d e f o r 2 0 h r a t I 1 5 " . u n l e s s
n o t e d o t h e r w i s e . ' T h e m e t h o d L r s e dt o e s t i m a t e t h e s e n u m l r e r s
is the ratio of the
is described in ref 24. "'Alcohol/carbonyl"
a l c o f t o l - a n d c a r b o n l l - c o r - r t a i n i p gp r o d u c t s d e r i v e d f r o m t h e a l k o x y
moiety of the copper(l) alkoxide. 'r Decompositiort temperaturc
85'. " Decomposition temperature 100". / Decomposition temp e r a t u r e1 6 0 " .
of al cohol i cto carbonyl -contai ni ngproducts i ncr eased
si gni fi cantl yas the sol ventw as changedfrom r elat ively
i neffecti vehydrogen atom donors stl ch as pe nt ane or
tol uene tcl an efl i ci ent donor, tetrahydrofur an, and
r h o s e ( c . g . , c o p p e r ( l ) 2 - p e n t o x i d e 3, - p e n t o x i d ec. y c l o b u t o x i d e . a n c l 1 , 1 - d i p h e n y l m e t h o x i d ef o) r w h i c h i r
c h a n g ci n s o l v c n t h a c l n o s i g n i f i c a n it n f l u e n c eo n t h i s
r a t i o . T h c s ey i e l d sa r e r e a s o n a b l yr e p r o d u c i b l e :s m a l l
v a r i a t i o n s r n a y b c d u e t o a d v e n t i t i o u sh y d r o l y s i si n
some of the sampl es. The physi calappearanceof all
o f t h c s a n t p l e sd t r r i n gd e c o m p o s i t i o nw a s s i m i l a r ,w i t h
t w o e x c e p t i o n s : c o p p e r ( l ) c y c l o h e x o x i d ea n c l c y c l o pe-ntoxi dew erc ntttch l ess sol ubl e than the ot hcr
c o p p e r ( l )a l k o r i d e se x a m i n e da, n d t h e i r d e c o n r p o s i t i o n s
w ereat l easti n part hcterogeneol l s.
The hi gh yi el ds of al cohol s observed i n decom posi ti onsof the fi rst group of al koxi desi n so lr 'ent sof
hi gh hydrogen atonl donor capabi l i ty. and th e var iati on i n thi s yi el d on changi ngthe sol vent.are qualit ati vel y compati bl ervi th the i ntermedi acyof free alkoxy
radi cal s i n the decomposi ti ons. It i s di fl i cu lt t o esti mate quanti tati vel ythe changei n the rati o of alcoholto carbonyl -contai ni ngproducts expectedon changing
sol vent i n these reacti ons, assumi ng an alkoxy
radi cal to be an i ntermedi ate. si nce a nu m ber of
reacti ons (radi cal combi nati on and di spropor t ionati on. attack on sol vent. reacti on w i th undecom p o s e d c o p p e r ( l ) a l k o x i d e ) a r e c o n c e i v a b l yo p e n t o
such a racl i cal . Ftrrther qLl al i tati vesupport f or t he
i ntermedi acyof free al koxy radi cal si n these r eact ions
of fragmenta t ionsand
w as provi ded by the obsern' ati on
ri ng cl osurcscharacteri sti cof al koxy radi cal si n cer t ain
. h u s . t h e r m a ld e c o m p o s i t i o n
t h e r m a ld e c o m p o s i t i o n s T
o f c o p p e r ( t )n - h e p t o x i d ea t 7 0 ' i n t o l u e n e y i e l d e d 1 and dodecane. Th e f or m aheptanol , n-heptal dehyde,
ti on of dodecanecan best be expl ai nedas the r esult of
2833
700
n-CzHr;OCu-*
rr-CzHrrOH* I-CoFITaCHO + rt-Cr,:Hro
PhCHs
6t%
207;
127;
the fragmentation of an intermediateheptoxyl radical
to an n-hexyl radical, and subsequentcombination of
tw o of t hes e r ad i c a l s .2 5 S i mi l a rl y , th e rma l decomp o sit ion of t he c op p e r(l ) s a l t o f 4 -p e n te n -1 -oal t 90' i n
26
toluene yielded 3-4% of 2-methyltetrahydrofuran,
The behav ior o f p ri m a ry a l k o x y c o p p e r(l ) compounds on thermal decomposition,and of cyclohexoxya n d c y c lopent ox y c o p p e r(l i),n d i c a te sth a t th e d o mi nant
mechanism for decomposition of these substances
generatesfree alkoxy radicals. Establishing a mecha n is m f or t he r e m a i n i n g s e c o n d a ry a l k o x y c opper(l )
compounds examined is less straightforward, although
se v er allines of ev i d e n c ea re c o m p a ti b l ew i th a mecha n is m inv olv ing e l i m i n a ti o n a n d s u b s e q u e n treacti on
o f c opper ( I ) hy dr i d e . F i rs t, th e re l a ti v ei n s e n si ti vi tyof
p ro duc t dis t r ibut i o n s fro m d e c o mp o s i ti o n o f these
t o t he h y d ro g e nd o n o r a b i l i ty o f th e sol vent
su b s t anc es
i s ex pec t edf or a m e c h a n i s mi n v o l v i n g g e n e rati onand
co ns um pt ion of a n i n te rme d i a te c o p p e r(l ) h ydri de.
Second,an effort to detect fragmentation of the cyclob u ty l r ing dur ing th e th e rm a l d e c o mp o s i ti o no f copper(l) cyclobutoxide was unsuccessful: the only products
observed were cyclobutanol and cyclobutanone. The
oxidation of cyclobutanol has been the object of careful
stu dy :27 it s t wo-e l e c tro n o x i d a ti o n l e a d s to cycl ob u tanone, while i ts o n e -e l e c tro no x i d a ti o n l e ads al mo s t ex c lus iv elyto ri n g -o p e n e dp ro d u c ts . Al though
th e r eac t ion c ond i ti o n s u s e d to e ffe c t th e th e r mal deco m pos it ionof c op p e r(l )c y c l o b u to x i d ea re s i g n i fi cantl y
d i ffer entt han t hos e o f R o d e k , th e o b s e rv a ti o n sthat no
ri n g- openedpr odu c ts w e re c b ta i n e d ,2 sa n d th e yi el ds
o f ring- c los edpr o d u c ts w e re g o o d (T a b l e III ), both
p ro v ide s t r ong s u p p o rt fo r th e c o n te n ti o n that the
cyc lobut ox y r adic a l i s n o t a n i n te rm e d i a tei n t hi s deco m pos it ion. B oth o b s e rv a ti o n sa re a l s o c o m pati bl e
w i th a dec om posi ti o nm e c h a n i s mi n v o l v i n g e l i mi nati on
o f c opper ( I ) hy dr i d e . T h i rd , i f c o p p e r(l ) h y dri de i s
g e n er at ed in t hese d e c o mp o s i ti o n s ,i t m u s t conrert
co p per ( I )alk ox ide sto a l c o h o l s(e q 4 ) a t a ra te that i s at
l e a st c om par ableto i ts ra te o f fo rm a ti o n : th e r ati o of
th e y ields of alc o h o l s a n d k e to n e s p ro d u c e d i n the
th e r m al dec om po s i ti o nn e v e r fa l l s mu c h b e l o w uni ty,
a s i t m us t if t he el i m i n a ti o no f c o p p e r(I)h y d ri d e (eq 3)
w e re t o be r apid c o mp a re d w i th i ts s u b s e q u entreacti o n . E x per im en ta l l y ,re a c ti o n o f c o p p e r(l ) h ydri de' :e
wi th equim olar q u a n ti ti e s o f e i th e r c o p p e r(l) cycl oh e x ox ide in t oluen e o r c o p p e r(I) 3 -p e n to x i d ein ether
a t 1 00o r es ult s in c o n v e rs i o no f a l k o x v m o i eti es en( 2 5 ) F o r c o m p a r i s o n , r r - b u t o x yr a c l i c a l s ,g e n c r a t e da t 1 9 5 " i n t h c
v a p o r p h a s c , c l c c o n r p o s et o p r o p y l r a d i c a l s t o t h c c x t c n t o f 2 9 1 i , :
E . R . B e l l , J . H . R a l c y , F . F . R u s t , F . H . S e u b o l d ,a n d W . E . V a u g h a r . r ,
D i s c a s sF
. a r a d a yS o c . ,N o . 1 0 , 2 4 2 ( 1 9 5 1 ) .
( 2 6 ) I r r a d i a t i o n o f t h c n i t r i t e c s t c r o f 4 - p c n t e n - l - o lr e s u l t si n y i c l c l s
o f c y c l i z c dp r o c l u c t su p t o 6 8 7 J : R . D . R i e k e a n d N . A . M o o r c , T e t r a h e c l r o nL e t t . , 2 5 , 2 0 3 5( 19 6 9 ) .
( 2 7 ) l < . M c y c r a n c l J . R o i . e k ,J . A r t t e r .C h e n t .| o c . , 9 4 , 1 2 0 9( 1 9 1 2 ) :
J . R o 6 e k a n c lA . E . R a d k o w s k y ,J . O r g . C h e n t . , 3 8 .8 9 ( 1 9 7 3 ) ; J . A m e r .
Cltent.Soc.,95, 7123(1973).
( 2 8 ) T h c o b s e r v a t i o nt h a t n o b u t y r a l c l c h y d co r s u b e r a l c l e l . r y rdvec r e
c l c t c c t c ci rl - trh i s r e a c t i o ni s n o t n c c e s s a r i lvyc r y s i g n i f i c a n ts, i n c cc o p p c r ( l )
a l k o x i d e s a r c s u f f i c i c n t l ys t r o n g l y b a s i c t o d e s t r o y s c u s i t i v ec a r b o n y l
c o n r l r o u n c lusn d e r t h e c o n d i t i o n so f t h c s cr c a c t i o n s .
( 2 9 ) G . M . W h i t e s i d e s ,J . S a n F i l i p p o , J r . , E . R . S t c c l r o n s k y a
, ncl
C. P. Casey,JA
. t n e r .C h e r t rS. o c . , 9 1 , 6 5 4 2 1 1 c 1 6J9.1At . D i l t s a n d D . F .
(
1
9
6
8
)
;
S l r r i v c r ,i b i d . , 9 0 . 5 7 6 9
9 1 , 4 0 8 8( 1 9 6 9 ) t G . M . W h i t c s i c l casn c l
J . S a r rF i l i p p o , J r . ,i b i d . , 9 2 . 6 6 lI ( 1 9 7 0 ) .
tirely to alcohol; no ketones were detected in either
reducti on. Thus the transformati on of c opper ( I )
al koxi des to al cohol s by copper(l ) hydri de is r apid.
Fourth, i f copper(l) hydri de w ere produced dur ing
thermal decomposi ti on of copper(l ) al koxi des, som e
quantity of molecular hydrogen might be found among
the products of the decomposi ti on,si nce therm al decomposi ti onof copper(l )hydri deto hydrog' eni s a r apid
reacti on under the condi ti ons encounteredin t hese
reacti ons. E xami nati on of the thermal decomposit ion
products of pentane sol uti ons of copper(l ) cyclobutoxi de and 2-pentoxi dei ndi cated the presenceof approxi matel y 1[ mol ecul ar hydrogen based on copper
al koxi de; those from copper(t) n-butoxi de an d cycloyi el d s. The
hexoxi deal so show ed smal l (-0.l -0.2[)
from
decomposition
detected
hydrogen
quantities of
of copper(l ) cycl obutoxi deand 2-pentoxi dear e only
4-6% of that requi redto accountful l y for the dif f er ence
i n the yi el ds of ketone and al cohol generatedin t hese
reacti ons; neverthel css,they are agai n com pat ible
w i th the presenceof copper(l ) hydri de i n the decom posi ti on. Fi nal l y, bri ef exami nati onof the ki net icsof
these thermal decomposi ti onsreveal edbehavior ver y
si mi l ar to that observed both by K ochi 2(' ' 30and by
S tedronsky;rrfor the thermal decomposi ti onof alkylcopper(l) compounds in which the elimination of
c o p p e r ( l ) h y d r i d e i s o f e s t a b l i s h e di m p o r t a n c e : d e composi ti onof copper(l ) 2-pentoxi dei n pentaneshows
an i nducti on peri od of vari abl edurati on, fol l owed by a
decomposi ti onw hose ti me course vari es from sam ple
to sampl e. The i nducti on peri od can be el i mi nat edby
the addition of 5 mol % copper(l) hydride. Curiousl y, the ki neti cs of the thermal decomposit ion of
c o p p e r ( l )n - h e p t o x i d se h o w ss i m i l a r ,e r r a t i c ,b e h a v i o r .
Discussion
The reacti on of methyl copper(l )(and presum ably
other thernral l y stabl e, basi c, organocopp er ( l) r ea g e n t s ) 3E2 - 3 4w i t h a l c o h o l sa n d p h e n o l sp r o v i d e so n e
c o n v e n i e n tr o u t c t o c o p p e r ()l a l k o x i d e s a n d p h e n o x i d e s : m a t e r i a l so f s i m i l a r r e a c t i v i t y m a y a l s o b e
obtai ned by reacti on betw een l i thi um al koxides and
cuproLrschl ori de. The tw o types of reacti onsi n which
thesereagentssecmto hav' ei mmedi atesyntheticpot enti al are thcl sei nvol vi ngthe formati on of ether l inkages,
parti cul arl y by di spl acementof hal i de i on fr om an
aromati c nucl eus, and those requi ri ng the t her m al
' the f or m er
generati onof pri mary al koxy radi cal s.:ri In
reacti on, copper(l ) al koxi des seem cl earl y super ior t o
( 3 0 ) K . W a d a , M . T a r l u r a , a r - r dJ . I ( o c h i , J . A m e r . C h e m . S o c . , 9 2
6656(re70).
(31) E. R. Stcdronsky, Ph.D. Thcsis, Massachusctts Irlstitutc of
Technology, Carrbriclgc, Mass., I 970.
(32) T. Cohcn and A. H. Lcwin, J. Amer. Chent. Soc., 88, 4521
( 19 6 6 ) .
( 3 3 ) A . C a i r n c r o s s , J . R . R o l a n d , R . M . H e n c l e r s o r . t ,i l t t d W . A .
S h c p p a r c l ,J . A r t r e r . C h e m . 5 o c . , 9 2 , 3 l 8 7 ( 1 9 7 0 ) .
(34) T. L. Cohcn and R. A. Scharnbach, J. Amer. Chem. Soc., 92,
3189( r970).
( 3 5 ) A b r i c f c r a n r i n a t i o n o f t h c t h e r r t r a l c l c c o r t t ; r o s i t i o r lo f c o p l l c r ( [ )
phcnoriclcs was carriccl out in thc hope thtt this rcaction rnight gcltcratc
l r h c n o x y r a c l i c a l s ,a n c l n r i g h t a c c o r c l i n g l y l t r o v i c l e a r r r c t h o d o f o x i d a t i v c l y
couplirrg phcnols. Thc rcstrlts of this study rvcrc clisappoir-rting: alt h o u g h d i g l l ' 1 1 1 gs o l u t i o n s o f c o p p c r ( I ) 2 , 6 - c l i n r e t h y l p h c r r o r i c l c y i e l d c c l
, 1 , 4 ' - c l i h y c l r o x y - 1 , 3 ' , 5 , 5 ' - t c t r a r r r c t h y l t r i p h c n y li r t y i c l c l s L r p t o 6 0 l l o r l
were also
rapicl clccorlpositiort at >100o, r'ttuch lorvcr yiclcls (.'20'l;)
obtainccl unclcr apparcntly sirnilar conclitions. Thcrrnal dcconrposition
of copper(l) phcnoriclc l"icldccl r.nirturcs of clihydrorybiphenyls irl no
m o r c t h a n 5 i ' , ,y i c l c l . D c t i r i l s o f t h c s c c x t l c r i m c r t t s r n a y b e f o u n d i n t h e
Ph.D. Thcsis of .J S. Sadon'ski, Massachusctts Institute of Tcchnology,
Carnbridgc, Mass., 1972,
o.l-Copper(l)Alkoxides
Whitcsitles,et al. I S.r'ntlrcsis
2834
o th e r pr es ent ly a v a i l a b l e re a g e n ts . T h e a b i l i ty of
co p per ( l) t o f ac i l i ta te re a g e n ts th a t i n v o l v e formal
n u c leophilic dis pl a c e me n tsa t s p 2 c a rb o n c e n ters i s
w e l l k nown, aand e v i d e n c eh a s b e e np re s e n te dth a t these
re ac t ions m ay in s o m e i n s ta n c e si n v o l v e fre e -radi cal
i n ter m ediat es . 3: W e h a v e n o c o n c re tee v i d e n ceconce rn ing t he m ec h a n i s mo f th e d i s p l a c e m e n to f hal i de
i o n f r om ar om at ic n u c l e i b y c o p p e r a l k o x i d c s , S mal l
q u a nt it ies( - l , " A o f b i p h e n y la re o b s e r' e d i n re acti ons
w i t h p h e n y li o d i d e : t h i s o b s e r v a t i o ni s c o n s i s t e nw
t ith,
b u t does not dema n d , e i th e r a fre e ra d i c a l o r a n aryl co p per int er m edia tei n th e re a c ti o n . T h e p ro nounced
e ffec tof s olv ent s ,p a rti c u l a rl yH MP A, o n th e reacti on.
th e s ugges t ionof ra d i c a l c h a ra c te r. a n d th e faci l i ty
w i th whic h alk ox id e so f c o p p e r(t)(a s o p p o s e dto other
m e t a l s ) p a r t i c i p a t ea r e c o m p a t i b l e w i t h m e c h a n i s m s
o f t h e S n u l t y p e , 3 2 ' 3b6u t o x i d a t i v ea d d i t i o n t o C u ( l )
m i g h t a l s o b e i n v o l v e d , 3a
Tn d a d d i t i o n a l w o r k i s r e q u i r ed t o def inea m e c h a n i s mc o n v i n c i n g l y .
A s a m e t h o d o f g e n e r a t i n gp r i m a r y a l k o x y r a d i c a l s .
th e t her m oly s is of c o p p e r(l ) a l k o x i d e s o ffe rs at the
sa m e t im e t he ad v a n ta g e sth a t th e s e s u b s ta n cesare
m u c h e a s i e rt o o b t a i n . a n d s a f e r t o m a n i p u l a t e ,t h a n
a re p r im ar y alk y l p e ro x i d e s a
, n d th e d i s a d v a n tagethat
th e y ar e m or e s en s i ti v eto a i r a n d w a te r th a n these
peroxides.
T h e e x a m i n a t i o no f t h e m e c h a n i s m so f t h e r m a l d e c o m p o s i t i o n so f c o p p e r ( l )a l k o x i d e sp r o i ' i d e st w o c o n v i n c i n g ,i f q u a l i t a t i v ep, i e c e so f e v i d e n c ei n d i c a t i n _t e
hat
fre e alk ox y r adic a l s a re i n rp o rta n t i n te rme d i a tesbct w e e n p r i m a r y c o p p e r ( l )a l k o x i d e sa n d p r o d u c t s : t h r :
r e s p o n s eo f p r o d u c t y i e l d st o c h a n g e si n t h e h y d r o g e n
a t o m d o n o r a b i l i t y o f t h e s o l v e n t .a n d t l r e p r o d u c t i o n
o f fragm ent at ionan d c y c l i z a ti o np ro d u c tsc h a ra c teri sti c
o f a l k o x y r a d i c a l s . T h e s ed a t a d o n o t r e q u i r ee i t h e r
th a t a f r ee- r adic a lme c h a n i s mb e fo l l o w e d e x cl usi rel y
( a l t h o u g h i t z i p p e a r st o b e a d o n r i n a n t p a t h w a y f o r
p r i m a r yc o p p e r ( l )a l k o x i d e s )o. r t h a t t h e a l k o x y r a d i c a l s
n e ce s s ar ilybe gen e ra te db y h o n to l y s i so f a n o xygen
c o p p e r b o n d ( a l t h o u g h t h i s p a t h w a y s e e n t su p r i o r i
t h e m o s t l i k e l y ) . R e g a r d l c s si t. i s e r i d e n t t h a t a t l c a s t
o n e addit ional m e c h a n i s m -m o s t p ro b a b l l , i n v ol vi ng
th e gener at ionand re a c ti o n o f c o p p e r(l ) h y d ri dc-i s
o p e rat iv e in t he t h e rma l d e c o m p o s i ti o no f s e condary
a l k o x y c o p p e r ( lc) o m p o u n d s . T h e e v i d e n c es u p p o r t i n g
th e inv olv em ent o f c o p p e r(l ) h y d ri d e i n th i s second
me chanis mis nr or e c o mp a ti b l e th a n o b l i g a to ry: the
n a tu r e and r elat iv e y i e l d s o f d e c o mp o s i ti o np roducts
a re relat iv elyins en s i ti v eto s o l v e n t: m o re k e to ne than
a l co hol is pr oduc e d i n c e rta i n o f th e d e c o mp osi ti ons:
tra ces of hy dr ogen a re d e te c te da m o n g th e p ro ducts:
co p p er ( l) hy dr ide r a p i d l y re d u c e sc o p p e r(l ) a l koxi de.s
to a lc ohols . T heseo b s e rv a ti o n sa re a l l v e ry s i mi l ar to
t h o s e m a d e i n e s t a b l i s h i n gc o p p e r ( l ) h y d r i d e a s a n
i n te r m ediat ein t he th e rm a l d e c o mp o s i ti o no f n -butyl (tri -n - but y lphos ph i n e )c o p p e r(la),
n d m a k e a n a n al ogous
me chanis m f or t he d e c o m p o s i ti o n o f c o p p e r( l ) al ko xi d esat t r ac t iv e.
Th e ident if ic at io no f th e s etw o me c h a n i s m sd oes not
clarify the structural factors that control the path
( 3 6 ) J . F . B u n n c t t ,, 4 c c o u r t tCs h e r n R
. e s . . 5 ,1 3 9( 1 9 7 2 ) : J . A . Z o l r e r v i c z
a r r dT . M . O e s t r e i c h , J A
, n c lr c f c r c u c e s
. r t r e r .C h e m .S o c . , 9 5 , 6 8 6 3( 1 9 7 3 ) a
c i t e di n c a c h .
( 3 7 ) N u c l e o p h i l i cc o u p l i n go f g o l d ( I ) a t e c o m p l e x e sw i t h a l k y l h a l i d es
i n v o l v e so x i d a t i v e a d d i t i o n o f t h c a l k y l r n o i e t y t o t h c g o l c l a t o m : A .
T a m a k i a r r cJl . I ( o c h i , J . O r g a n o m e t a lC. h e m . , 5 l , C 3 9 ( 1 9 7 3 ) .
Journctl of the American Cltemical Societl' I 96:9 I Muy
l, 1974
fol l ou' ed bv a parti cul arorganocopper(f)contpound in
i t s t h c r m a l d c c o m p o s i t i o n . I n c l e e dt.h e e l i n t i n a t i o no f
copper(l) hycl ri cl from
c'
a copper(l) al koxi dew ould seenl
energeti cal l ymore attracti vethan i ts el i mi nati on f r om
a c o p p e r ( l )a l k y l , b o t h b e c a u s et h e e n e r g yc h a n g ea s soci atcdw i th the conversi onof a carbon-oxyge nsingle
b o n d t o a c a r b o n y lg r o u p i s m o r e f a v o r a b l et h a n t h a t
o f a c a r b o n - c a r b o ns i n g l eb o n d t o a d o u b l e b o n d , a n d
becausea coppcr(l )-orygen bond i s expectedto b e m or c
p o l a r ,a n d l e s ss u s c e p t i b lteo h o m o l y t i cs c i s s i o nt,h a n a
c o p p e r ( l )c a r b o n b o n d . T h e f a i l u r e o f t h i s r e a s o n i n g
suggests
that othcr factorsenti rel y-the structureof t he
organometal l i caggregates,
the presenceo1' trac er net al
c a t i i l y s t s t. h c a r a i l u b i l i t y o f v a c a n t c o o r d i n a t i o l rs i t e s
on the metal may ul ti ntate' l yci eterni i nethe deconr p o s i t i o n m e c h a n i s n ra
s n d t h c r r l a l s t a b i l i t i c so f t h e s e
and other orgrrrlr' rr11r.tl
I Ii c rrcagcnts.
ExperimentalSection'
Iodofbis(di-n-but1'l sulfido)]copper(I).
Commercial coppcr(l) iod i d e ( 1 9 5 g , 1 . 0 - 5n r o l ) i v a i s s t i r r e d w i t h d i - l - b u t y l s u l f i d e ( 2 9 0 g , 2 . 0 0
ntol) in a 500-nrl erlenrncl'er 11ask. Thc reaction nrixturc was
*,arnrecl to.3() lirr l0 nrin and thc rcsulting amber licluicl filtered
tltroLrgh a Buchncr furrnel and stored at room temperature.
(1.4 g,
\Ieth1'lcopper(I).
Iodo[tris(di-ri-buty,l sulfido)]copper(l)
2.8 mmol) and 30 rll of ether u'ere added to a flame-dried. serunlstoprpered, -10-ml ccntrifuge tubc containing a Teflon-coated stirring
bar aud six to eight 3-nrnr glass beads to aicl in subsec;ucltl ltctcrogeneous reactious
tlrc alcohols.
Thc solLrtioll wil\ coolecl to
- 7 8 i n a [ ) r 1 l c e" r ii tsho p r o l - r r l a l c o h o l b a t h a n d n r e t l r 1 , l l i 1 1 1 l l ' r(r1n. - 5
n r l o f a 1 . 6 . V s o l u t i o n i n c l i e t h y , le t h c r . 2 . 4 m r n o l ) r v a s a d d e d . p r o ducing an inrnrcdiatc precilritate of bright lellow methylcopper(l).
The solicl wa\ corrpacted b1 centril'Lrgati()n at roont tcmperatLlre
ancl the \Llllcrnatant liquid rcrlovecl b1' cannula.
Fresh etlrcr (30
r r l ) w a s a c l c l e c lu ' l r i l e k e e p r n g t h e n r e t h l , l c o l - r p e r ( l ) c o l c i i n a D r - v l c e
isolrrolrl'l alcohol batlt. ancl the tLrbe w:rs shaken arrd ccntriluged.
The etlter was agarin renrovcd and tlte washing prrlcerlure rcpeated
an additiorral two times.
Copper(l) alkorides \\cre prcparccl b1 a contntol't proccdurc.
i l l u s t r a t e d h c r c l r y t h c 1 ' r 1 e 1 ] n r s t i o no f c o p p e r ( l ) n - b u t o x i c l c .
To a
suslrension of 2.-l nrnrol of ntetlrvlcopper(l). preparcd as descritrcd
above. was acldecl rr-but1l alcohol (0.22 ml. 2.-1mntol).
l-he reaction nrixture \ras stirred at 0 for 3 hr under nitrogen.
Thc resulting hontogcr-lcolrssolution uas cooled to -78' ; copper(l) rr-but o r i d e p r e c i p i t a t e d a s a l i g h t l e l l o w ' p o i . r ' d c r . T h e s o l i d \ , \ ' a sc o m -
( 3 8 ) A l l r l c l t i n g p o i l r t s a n c l b o i l i n g l . r o i n t sl r r c u r l c o r r c c t e d . I n f r a r c c l
spcctril rvcrc rictcrurinccl u ith a Pcrkin-Elnrcr, Modcl 237, grating
s 1 : r c c t r o l r l - r o t o n r c t c r .N n r r s l - r c c t r a\ \ ' c r c c l c t c r n r i n c c li v i t h a V a r i l r n T - 6 0
nnrr spcctronlctcr. Mass spcctra wcre clctcrrninccl on a HitachiPcrkin-Elrncr R M U-6 nlass sl)cctronrctcr. Con.rttustion analy'scsu'crc
M ' 1 1 r , 1 ' g sN1' [ i c r p l t r b s ,L t c l . , . l ' l r l c l i i t r l t t l - r t l l i s ,I ' d .
A.irly.tillcrfclrtnctl 111'
cal glpc analyses u'crc pcrforrlccl on F&M
Moclcl 810 anci PcrkinElrner Moclcl 990 llurnr' ionizltion iustrun.rcr.rts. Hyclrogcn analyses
r,l'crccarriccl out Lry glpc using nitrogcn carricr gas, a thermal concluctivitl, clctcctor, anrl rncthlnc lls intenlll stirnclurcl. Absolr.rtc yiclcls
o f l r r o c l u c t s r v c r c c a l c u l a t c c l f r o r . r . r1 ' r c a kl r r c l r s u s i n g i n t c r n a l s t a n c l a r c l
t ec h r r i q u c s , w i t h r c s p o n s c f i r c t o r s o b t a i n c r l f r o n r u u t h c n t i c s a r . n p l c s .
Dicthyl cthcr rncl tctrahydrofuriill wcrc clistillcclfronr lithiur.rr ultrnrir u i - r n ih y c l r i c l c o r c a l c i u n r h y c l r i t l c b c f o r c u s c . D i r r r c t h o r y c t l r a r t c a r t c l
llcntanc rvcrc clistillccl fronr clisocliunr [rcuzolrhcrrouc ciianion unclcr
n i t r o g e n : p y r i c l i n c u n c l l . r c n z e r r cw c r c c l i s t i l l c c l f r o m c a l c i u n r h y d r i c l c
u n d e r n i t r o g e n ; h c x r r r n e t h y l p h o s p h o r a n r i c l er v a s d i s t i l l c c l f r o r r r s o d i u n r
a t r c c l u c c d l r r c s s u r c . A l c o h o l s r v c r c d i s t i l l c c l , c l r i e c lo l ' c r 3 A r . n o l c c u l a r
s i c v c s , a n c l c l c o r y ' g c r r a t c cul s i n g a s t r c a r l l o f n i t r o g c n . O r g u u i c h a l i c l c s
r v c r c p a s s c d t h r o u g h a c o l u n r r . ro f u l u m i r r a , a n d c l c o r y g c n a t c c l u s i t r g a
strcanl of nitrogcn.
H a l i c l c - f r e c n r c t h l , l l i t h i u m ( 1 . 6 . ' 1 1i n c t l . r c r ) w a s
purchascd frorn Footc Mincral Corp.
C y , ' c l o p c n t y l - , r r - b r . r t - ' * l -a, r t c l
t c r l - b r - r t y l l i t l ' r i r . r r nr c a g c n t s \ \ ' c r c s u p p l i c d b l ' F o o t e M i n c r a l C o r p .
Alfa Irtorgunics, Inc. Lithiunt
s c c - B u t _ n - l l i t h i u n r\ \ ' l s s u l r p l i e c l b l
jrrt All
r e a g c n t s * , c r c a n u l v z c c l b 1 , t h c G i l r l a n c l o L r b l et i t r a t i o n n r c t l t o c l .
reactior.rsinvolving organoluctallic rcagcnts werc carriccl out utrdcr
p r c p r , r r i f i c r ln i t r o g c n , u s i n g s t ur r c l a r d i n c r t a t m o s p h c r c t c c h n i q u e s , l { t
( 3 9 ) H . G i l n r i r n . F . l ( . C a r t l c c l g c , a n d S . - Y . S i n r , , l. O r g c r t r o n t e t a l .
C h e m . , l . 8 ( 1 9 ( r - j .; t 6 . M . W h i t e s i c l e s , C . P . C a s c y , a n c l J . I ( . I { r i e g c r ,
J . A n t e r . C h c t r t . ^ S o c .9, 3 . 1 3 1 9 ( 1 9 1 1 ) .
(10) D. F. Shrivcr, "Thc Manipulation of Air-Scnsitivc Cor.r.rpouuds,"
M c G r a u , - H i l l , N c r r Y o r k , N . Y . , 1 9 6 9 ,C h a p t c r 7 .
2835
pacted br ccntrifugation at - 78" and the supernatant licluid
r e m o v e c lb y c a n n u l a . F r e s h e t h e r w a s a d d e d w h i l e k e c p i n g t h c
c o p p r e r ( l ) r : - b L r t o r i ccl o
e l c l i n a D r 1 ' I c e i s o l t r o l r l l a l c o h o l b a t l - ra. r r c l
the tLrbc was shaken ancl centril'ugecl. The ether was again rem o v e c la n c l t h e w ' a s h i n gp r o c e c l u r er e p e a t e c l . T h e l i e l c l s ( r i t l c i t r l r u )
o f c o l r p e r ( l ) a l k o r i d e s o l r t a i n e c lL r s i n gt h i s p r o c e c l u r ew e r c r . l o t p a r t i c u l a r l y r e p r o c l u c i [ ' r l el.' o r t w o r e a s o n s : t h e h e t e r o g e n e i t . vo f t h e
r e a c t i o n i n e t l r e r a n c l t h e r e s t r i c t i o n s i r n p o s e c lb , l t h e m e t h o c l o f
anall'sis.
W h e n t h e a l k o r i d e w a s g c n e r a t e da s a r r i n t e r m e d i a t e .t h e r e a c t t o n
w a s h o m o g e n e o u s( p y ' r i d i r r ed i s s o l v e sm e t h y l c o p p e r ( l ) ) .a n c l a t w ' c t f o l c l e r c e s so f a l c o h o l r v a s u s e d . W h e n t h e a l k o x i c l ew a s t o b e i s o l a t e c l . t h c r e a c t i o n r v a s h e t e r o g e n e o u s( d i e t h y l e t h e r d o e s n o t c l i s . s o l v e r n e t h y l c o l - r p e r ( l ) ) .a n d I e q u i v o f a l c o l r o l r , r ' a su s e c l . T h e
w a s h i n g a n c i c e r r t r i f u g i n gh a d t o b e c l o n e a t - 7 8 . a s t h e a l k o x i c l e s
a r e v e r ) e t h e r s o l u b l ea t h i g h e r t e n i p e r a t l l r e s . T l r e s en t a n i p u l a t i o n s
were technically clifiicult. l}ecause the acid cluench regeneratecl
t h e s t a r t i n g a l c o h o l . c a r e h a d t o b e t a k e n t o r e n t o v e e x c e s sa l c o h o l
before quenching the alkoxicle. ancl onl,l I ecluiv of alcohol rvas
u s e d . T h e i s o l a t e c lf i e l d o f ' a l k o x i c l e l r r o b a b l y v a r i e c l o v e r a r v i c l e r
range tharr did the nonisolated l,ielcl of alkoxide internrecliate.
A v e r a g e f i e l c l s( p e r c e n t s a n c l r a n g e s ) o b s e r v e c ll - o r v a r i o u s c o p p e r
a l k o x i d e s r v e r e : m e t h o r i c l e - 7 0 : r r - i r u t o x i c l e- . - 5 5 ( 4 8 - 6 6 ) : / c r t p h e n o x i d e . - - 1 - i( : - s
butoride -65 (52 83): cyclohexoride-80;
5 7 ) : a n c li s o p r o p o x i c l e - 5 0 .
, , \ n : r l y s i so f C o p p e r ( I ) . \ l k o x i d e s . T o a s o l L r t i o n o f c o 1 - r p e r ( l )
a l k o x i d e ( I : 1 m m o l ) i n e t l r e r a t 0 l v a s a c l d e d 0 . - 5n t l o f c o n c e n t r a t e d h 1 ' d r o c h l o r i ca c i c l . A d d i t i o n o f i n t e r n a l s t a n c l a r dp e r n t i t t c d
g l p c a n a l l ' s i so f t l r e r c s u l t i n g h o n r o g e n e o u ss o l u t i o n f o r a l c o h o l o n a
l5i'l Carbowax 20M on Chromosorb W coluntn. The col)pcr
c o n t e n t o f t h e s o l u t i o n w a s t h e n c i e t e r n r i n e db l , a d d i n g t o i t 1 0
m l o f c o n c e n t r a t e c rl r i t r i c a c i r i . c l i l L r t i n gt o 2 0 0 r l l u , i t h d i s t i l l e d
water. ancl anallzing follou.irrg the procctlure o1' Flasclrka anci
A l r d i n e . II
Small Scale Reactions of Copper(I) .\lkoxides with Orsanic
H a l i d e s . T h e p r o c c c l u r e su s e d f o r n t o s t o f t l r c s c r c a c t i o n \ \ \ r r e
s i m i l a r . a n d a r c i l l u s t r a t e c lh e r e [ ' r _trl - r cm c t l t o d u s e c lf o r r h c r c u c r r o n
o f c o p l t e r ( l ) n - b u t o x i c l e* ' i t h n - t r u t l l b r o m i c i c . A 2 . - l - n t n r o ls a r l g r l e
o f n T e t h y l c o p p e r ( l )r v a s p r e p a r e d . T h e b u l k o f t h c c t h c r u s e d i n
t h e f i n a l w a s h i n g w a s r e m o v e d .p y r i d i n e ( 2 0 m l ) a n c ln - b u t 1 l a l c o h o l
( 0 . 2 2 n t l . 2 . : l m r n o l ) r v e r ea c l c l e c a
i . n c l t h e c e n t r i t ' L r g tcu b e w a s c a l r p e r l
w i t h t l v o s e r L l l l s t o l l l l e r s . ( - l h c s c c o n c ls e r r e c l t o \ l o \ \ l l t c r a t c c l f '
l e a k a g e o f o x r g e n i n t o t h e 1 l a s k . ) T h e s o l L r t i o l \t ! a s s l i r r c t l l o r . r
h r a t 0 " : t h e n n - b L r t 1 'bl r o m i c l e ( 0 . 3 2 n r l . J . 6 m m o l ) r ' , a s a r k l r r l
a n c l t h e r e a c t i o n m i x t u r e w a s s t i r r e d f o r a n a r l c l i t i o n a lf J h r a r r o o r r r
t e m p e r a t u r e . A n a l 1 , ' s i sb 1 g l l t c o n a n 8 - [ ' 1 .1 0 " ; i T C E I , o n C h r o n r o s o r b W c o l u m n i n c l i c a t e da y i c l c lo l ' c l i - i r - b L rl t el t h c r o l ' 6 - 1 " , , .
Purification of Ciuprous Chloride.tr (-uprorr' chloride (-50 g)
w a s g r o u n d i n a m o r t a r w i t l r c r r . l 0 n t l o f | \ ' L r l l i r r i ca c i c l . T I t c
r e s u l t i n g p a s t e w a s a d d e d t o 7 ( ) 0 n r l o f ( r " , , s r r l l ' u r t ) L lrtrc i t l . I h e
s u s p e n s i o nr v a ss t i r r e df o r l 0 m i n ; t h c s u s p c n d e tsl o l i t l u n r l t l r r | 1 1 1 g
b l u e s u p e r n a t a n t l i q u i d w e r e s e p a r a l c d b _ rf i l t r a r i o n . T l r c t i l t c r c c l
s o l i d w a s r v a s h e d w i t h 3 0 0 n r l o f g l a c i a l a c e r i c a c i c l . 2 - 5 0n t l o f
e t h a n o l , a n d 2 5 0 r n l o f e t h e r . T h e o l l - ' u v h i t es o l i d r v a s d r i e d u n d e r
v a c u u m a n c ls t o r e d a t 5 ' .
Reaction of lodobenzene with Copper(I) l-Butoxide b5' the Rcaction of Lithium n-Butoxide with Cuprous C'hloride. Cuprous
c h l o r i d e ( 0 . 2 0 g . 2 . 0 n t n r o l ) n , a s a d d e d t o a s c r u n t - s t o p p c r e c l .l a n t c d r i e d , : 1 0 - m l c e n t r i f u g e 1 u t - r ec o n t a i n i n g a T ' e f l o n - c o a t c c ls t i r r i r r g
b a r . a n d t h c t u b e w a s l l L r s h e cui i t h n i l r o g e n . A s o l L r t i o no f l i t h i L r n t
n - b u t o x i d e .p r e p a r c d t r 1 r e a c t i o n o f 0 . 1 . 1 8g ( 2 . 0 m n r o l ) o f i r - l r L r t ] l
a l c o h o l w i t h 2 . 0 n r n r o l o f m e t h i l l i t l t i u n r i n - 5m l o f D M t : . w a s a c l d c d
a n d t h e m i x t u r e s t i r r e d f o r 3 0 m i r r . P . r r i d i n e( 2 0 n r l ) w , a sa d d e d t o
t h e r e s u l t i n g l e l l o w s o l L r t i o n .a n c l t h i s n t i x t u r e a l l o l v e c lt o r e a c t w ' i t l r
i o d o b e n z e n e( 0 . 6 1 c . 3 . 0 n t m o l ) f o r l 2 l r r a l r c l l u x . G l p c a n a l l s i s
i n d i c a t e dt l r a t r i - b u t l l l t h e n l l e t h e r l r a s p r e s e n ti n 9 8 ' ' . , t i c l d . b a s c d
o n c o p p e r ( l ) a l k o x i d e1 i e l d .
Reaction of lithium n-butoxide with iodobenzenein the prcsenceof
1 0 9 ; c u p r o u sc h l o r i d e r , v a sc a r r i e d o u t i n a n a n a l o g o u s m a n n e r , r v i t l - t
the exception that only 0.02 g (0.2 ntntol) of cuprous chloride u.as
used. Analysis on a 6-ft. 3:; OV-17 on ChronrosorbQ colrlmn
s h o w e d a 7 0 o , i y ' i e l do f n - b u t 1I p h e n l ' l e t h e r .
Prep:rrative Scale Reaction of Copper(I) .rtc-Butoxide with Bromobenzene. Dimethoxlethanc (30 nrl) and 2-butanol (,5.6 g.75
( 4 1 ) H . F l a s c h k aa r r cH
l . A b c l i n c , V i k r o c h i mA. c t u , 7 7 0( 1 9 5 6 ) .
( . 1 : ) R . N . I ( c l l e r a n c lH . D . W y ' c o f i 'I,t t o r g . S y t t . , 2 ,1 ( 1 9 4 6 ) .
m m o l ) w c r c a d d c - dt o a s e r u m - s t o p l r e r e df.l a m c - d r i e d . 1 0 0 - m le r l e n m e ) , c rl l a s k c o r r t a i n i n ga T c l l o n - c o a t e ds t i r r i n g b a r . T h e r e s u l t i n g
s o l L r t i o nu ' a s c o o l e d i r r a r r i c e b a t h a n c l n r e t h l ' l l i t h i L r n r( . 1 7n r l o f a
1.6 ,\r solution in ctlrer. 75 rnmol) u,as added slowl-r,. Cuprous
c h l o r i c i e ( 7 . - 5g . 7 . 5 r n n r o l ) r v a s p l a c e d i n a s e r u n r - s t o p l l e r e c fl .l a n r e d r i e d . 5 0 0 - n r l .r o l r n c l - b o t l o m e df l a s k e q u i p p e d r v i t l r a T e f l o n - c o a t e d
s t i r r i n g t r a r a n d a s c r u l ' n - s t o p p c r e dr e l l u x c o n d e n s e r . T l r e a 1 r p a r a t u \ a n d i t s c o n t e n t s r e r e f ' l u s h e dw i t h n i t r o g e n . t h c l i t h i u m
. s c r ' - b u t o r i c i seo l u t i o n w a s a c l d e c l a
. nd the mixture was stirrcd for 30
P 1 ' r i c l i n(e2 0 0 n r l ) a n d b r o m o b c n z e n c{ | l . f r g . 7 5 m m o l )
min at 25
w e r e a c ' l c l e ct ol t h e r e s u l t i n g s o l u t i o n a n c i t h e r e a c t i o n m i x t u r e w a s
r e t l u r c d f o r l l l r r . S o h c n t \ \ ' a s r e n l o v e c lb y c l i s t i l l a t i o n t h r o u g h a
3 0 - c n i H o l z n r a n n c o l u n r n . a n c l t l - t cr e s i c l u er v a s c l i s t i l l e ctlh r o r - r g ht h c
s a m e c o l u r n n a t r e c l u c c cpl r c s s u r c .l i e l d i n g 5 . 1 g ( - 1 , 5 9 ;o) f . r c c - b u t 1 l
p h e n l ' le t h e r l r a v i n gb p 9 l ( l - 5 m m ) : n m r ( C C l ' ) 6 6 . 8 ( s . 5 . a r o m a t i c C H ) . . 1 . 0 ( m .l " O C H ) . 2 . 0 0 . 8 ( r n . 8 . C H r a r r c lC H , r ) .
Preparation Scale Reaction of l-Bromobutane with Copper(I)
P h e n o x i d e . A n r a g n e t i c s t i r r i n g b a r a n d 1 5 . 3 - r n n -gr l a s s b e a d s ( t o
i n c r c a s et h c r a t e o f s o l i d s o l u t i o n r e a c t i o r r sb 1 'g r i n c l i n g )r v c r e p l a c e d
i n e a c h o f t r v o 2 f f 1 - n r lc e n t r i f i r g e b o t t l e s . T h e b o t t l e s w e r e s t o [ ) l r e r c d . a n d l l a n r e c l r - r n d c rr t i t r o g e n . M e t h l , l c o l r l r e r ( I ) ( 5 0 m m o l )
w a s p r e p a r e c li n e a c l r 1 u b c . T o t l r e w ' a s h c csl u s l - r c n s i o nosf m c t h y l c o p p e r ( l ) i n c t l r c r ( - 5 0n r m o l ) r v a s a c l d e d8 . 8 m l o f l r h e r r o l( 0 . 1 m o l )
a n c l 1 0 0 m l o f p y r i c l i n c . T h e m i x t u r e w a s s t i r r e c lf o r 3 h r a t 0 ' .
B u t . v lb r o n r i c l e( 8 . { l - 5m l . 0 . 0 7 5 m o l ) w a s a d c l e dt o e a c h b o t t l e a n d t h e
m i x t u r e s r v e r c s l i r r e c la t r o o r 1 1t e m p e r a t u r e u n c l e rn i t r o g e r r I ' o r . 1 8h r .
TIre rcactiorr mirturcs werc poured or.lto ice ancl tlre corlbineci
organic prorlucts ertractecl into ether. Ammoniunr Irlclroride
( - 1 0 m l ) u ' a s u r l d c r l t o c o n r p l c r c o l l l l e r a s w a t e r - s o l u b l eC L r ( l l )
-fhc
sltecies.
c r t r a c t \ \ \ c r c w a s h e d * i t h a c l u e o u sK O H a n d r . l ' i t l t
ice watcr: tlre ethcr'\\a\ rcmorecl on a rotar) evalrorator. On
. . 3 g ( ( r 2" , , l r a s e d o t r t n e t l - t 1 l distillation urrtler rcclucctl pressLlrc9
lithir-rrl)of l-[rittrI plten1[ ether *as cltrtained: nntr (C'Clr) o
6 . 7 7 . 2 ( n r . 5 . a r o n . r a t iC
c H ) . . 1 . 81 . 0 ( t . l . O C H : r ) . 0 . 8 2 . 0 ( r l . 7 .
c H : a n r l ( - F { r : i r r c ( ' 1 , ) l 9 ( r 0 . 2 9 J 0 " 2 8 8 0 . l 6 ( x ) . l 5 ( x ) . 1 2 9 0c m 1 :
/ll c 1-50.
l)reparative Sc:rleReaction of I -Bromocl'clohexene rvith Copper(I)
T h c r e a c t i o n u a s c a r r i e c lo l l t o n a 7 0 - n r n r o l s c a l c i t r
l-Butoridc.
a m a n u c r a n a l o g o u r t o t h a l c l e s c r i t r cadb o v e : t h e r e a t c t i o nt i n r e w a s
2 J h r . A r ec l u c c r l p r e \ \ u r e c l i s t i l l a t i o n l i e l c l e d 3 . ( r g ( 3 3 1 , , ) o f
l - b r r t o r y ' c l c l o l r e r e n c : t r 2 ' D 1 . 1 1 6 3 5 :n m r ( C C l 1 ) 6 - 1 . 1 5 ( m . l .
. CH). 1.,s5
( t . l . O C H : ) . 0 . 9 - 52 . 0 ( m . l - 5 .C H : a n c lC H , ' ) : i r ( C C l r )
1 0 7 - 52. 9 ( X ) .I ( r ( r , 5l .- i , 5 0 .l - + 3 - i .13 7 . 5 .I 1 9 0c n r 1: r r " t , I 5 - 1 .
Reactionof Copper(l) Phenoxide with lodobenzene. A solution
o f l r a l i d c - f r c cn r e l h l l c o l - r p c r ( l()2 . 0 n r n r o l ) i n l 0 n r l o l ' p l r i c l i n c w a s
transfcrrccl to a flarlc-c'lried.-10-ml ccntrifuge tutre contairriug
p h e n o l ( 0 . 8 7 g . I 0 n r r n o l ) . a r t c l s t i r r c c la t 2 5 f o r 3 0 r n i n . T h c
r e s u l t i n g a r n [ ' r e rs o l u l i o n \ \ a \ t r a n s f c r r e c tl o a f l a r n e - c l r i e c l . , 5 0 - n t l .
r o u n t l - l - r o t t o n r c r l l a s k e c l L r i p p e cul . ' i t h a T e f l o n - c o z r t e csl t i r r i n g b a r
I r r r r l ' c l r r n t - \ i ( r l r l ) c l e (rlc t l L r rc o n r l e n s e r . l o c l o b e r r z e n(c0 . 6 1 g . 3 . 0
r l r . n o )l u l r ' l r r l r l c t l a r t t l t l r c r e a c t i o n t n i x t u r e r c l l u r e c l l - c l r l 2 h r .
a u S - f t . l - 5" , , C a r b o A n u l r : i : t r l 't h t r c u et i ( ) n r r r i r t u r el r y g l l r c r . r s i n g
r v a r 2 0 \ { c o l r r n . r ri.nr t l i c a t c t l a 9 - l " , , l i e l c lo f c l r p h e n y le t h c r .
C 1 ' c l o b u t : r n t l l\ \ i t \ p r c l - r a r c d u s i n g t l t e l l r o c e d l t r c o f C a s e r i o .
G r a h a n t . a n c l R r t b c r t s .I
Thermoll'sis of Copper(l) ,\lkoxides. Approxinralell 2-nrl
a l i c l u o t s o f c o p l r e r (I ) a l k o x i d e s o l u t i o l r \ \ c r c t r a n s f e r r c c l u n d e r
n i t r o g e n i n t o d r r S - n t n t P 1r c r t u [ ' r c s .t h c c o n t e n t s o f t h c t u b e s u ' e r c
f r o z e n i n l i q L r i dn i l r o g c n . a n c l t l r c t u b e s n e r e s c a l e du n c i e rv a c L l u m .
T h e t u b e s r v e r el t e a t c c i n a b o n r t ' ro v e n f o r t h e r e c l u r s i t et i m e . c o o l e c l .
a n i l o p e n c c l . l n t c r r t a l g l p c s t a r r c l a r c lws e r e a d c l e c la. r r c lt l r c n r i r t u r e s
r . r ' e r ea n a l l z e t l l r r g l p c . T h c c o l r l r e r c o n t e n t o l ' t h e s e s o l u t i o n s w a s
c l e t c r n r i n e cbl r t h e l r r o c e c l u r eo f F l a s c h k a a n c l A b d i n e . { t
Thermal Decomposition of Copper(I) \lkoxides in the Presenceof
C o p p e r ( I ) H v d r i d e . S o l u t i o r r s o f . c . , q ' . .c o p p e r ( l ) c y c l o l r e x o r i c l c
( - 5 . 0 m r - n o l ) i r r l 0 n r l o f l o l u e n e a n d c o i - r 1 r e r ( l )- 1 - p e n t o x i d e( 3 . 1
m m o l ) r n 1 0 n r l o f c t h e r \ ! e r e t r a n s f e r r e c lt o - 1 0 - r n cl e n t r i f u g c t L r b e s
c o n t a i n i r r gJ . 0 - m n r o ls a n r p l c so f c o p p e r ( l ) h y d r i d e . 2 e T h e r e s u l t i n g
m i r t u r c s u ' e r c c l e c o n r n o s eicnl s e a l e dt u b e s a t I l 5 a n c l a n a l v z e da s
c l e s c r i b e da L - r o v e .
A cknorvl edgment.W e thank P rofessorJan Roiek
of thi s probl enr.and for pr o! idfor a hel pfLrlcl i scussi crn
i nforn-rati on.
i ng us w i th unpubl i shecl
(43) \l . C. Clscrio, \\', I{. Grrrhunr, and.1. I). Robcrts, l-ctrutttdrort,
lr. l7l il960).
lVltirc.sides,
o.f'Crtpper(l'),llko.rides
ct al. ; S.t'nthesi.s