Journal
of Organometallic
Chirrr_v
Eketier
Publishing
Printed
in The Mthcrlands
Company
STUDIES
IN GROUP
)(xIV*.
STRUCTURE
HYDROSTANNATION
A. J. LEUSINK,
Institute
285
Amsterdam
IV ORGANOMETALLLC
CHEMISTRY
OF PRODUCTS
OBTAINED
IN THE
OF ETHYNES**
H. A. BUDDING
for Organic
Chemiw_v
AhJ
TNO,
J. W. MARSMAN
Utrecht
(The
Netherlanris)
(Received January 2nd, 1967)
INTRODUCTION
In a previous paper2 we have shown that in reactions of rrialkyltin hydrides
with alkyl ethynecarboxylates in the absence of solvents and catalysts a variety of
compounds are formed, e.g.:
R,SnH
+
H-CEC-COOEt
+
R,Sn
H\C_C/SnR3
+
+
Cd’
\
H’
-
‘COOEt
I
+
H
COOEt
R,S”’
H
\
“\,=C’”
+
COOEt
R&I-CGC-COOEt
P
lx
(Ia-Va, R = Me ; Ib-Vb,
\
m
II
R,Sn-CH,-CH,-COOEt
+
/
R = Et)
Similar reactions of trialkyltin hydrides with propynol, ethyl l-propynecarboxylate, cyanoethyne and diethyl ethynedicarboxylate led only to the formation
of the unsaturated I : 1 adducts3.
In the present paper the results of a further study of these reactions are presented.
RESULTS
Organotin monohydrides were brought into reaction with a variety of monoand disubstituted ethynes. The identity of the resulting products was established by
means of elementary analysis, infrared absorption spectroscopy and proton magnetic
resonance spectroscopy_ The yields of the several products were calculated from NMR
spectra and gas chromatograms of the reaction mixtures.
NMR data of the compounds identified in this and previous studies are
presented in Tables 1-3. In previous papers’s3 structural assignments were based
mainly upon the coupling constants, J(H-H),
of the oleftic protons and on the
*
Part XXIII: see ref. 1.
** Taken from the Ph.D. thesis of one of us (A.J.L.).
J. Organometal-
Chen,
9 (1967) 285-294
SrlR,
t 0.98
t 0.97
R=Mc
R= Et
R = Pr
\
b
t 2,50
t 2A9
t 2.47
d 6,23
d 6.26
d 6.25
d 666
d 612
0 6.67
d 5.93
d 5.90
d 5.90
q4.18
t 2.50
t 2848
s 3.67
s 3.61
s 3.60
s 3.73
s 3.73
s 3.69
s 3.70
s 3.68
s 3.71
s 3868
s 3.69
q 4,13
q4,15
q 4.18
q 4.21
(14.15
q 4.16
d 6026
d 6.24
d 6,66
d 6,71
d 5.91
d 5.90
1.5
7.7
7.7
19.3
19.5
19.5
12.7
12.6
12.7
3,o
2.9
3,o
1.5
19.5
19.5
12.6
12.6
2.8
3.0
7*1
7,l
7.2
7,2
7.1
7.2
7.1
61.0
69.0
65.5
60.0
59.5
-61
N 50.0
63.5
72.0
68.0
63.0
62.0
127.5
115.5
114.0
53.0
50.5
122.0
110.5
108.5
64.0
54.0
62.0
122.0
109.0
108.0
60.5
53.0
54.0
66.5
54.0
121.0
109.0
IO,0
64,O
66.5
61.0
61.0
60,5
53.5
12830
118.0
123,O
112.5
-66.5
-57
-55
?
114.0
113.0
56,5
65,O
F
”3
565
127.5
5
rA
?
k
63.0
55s
69,5
56.5
127.0
114.0
63.0
56.0
” Only multiplicitiescluc to H-N coupling arc given; s: singlet; d: doublet; t : triplet ;q : qunrtct. h Dowlield from tetramcthylsilane, internnl. ’ Coupling constants
with “‘Sn and ‘lgSn isotopes, respectively.
n
R,Sll
R = Et
d 7.65
d 7.63
d 7.63
R=Me
R=Et
R=Pr
(VIIla)
r
(VIIIb)
H~c=C\CO*Cll
(VIIIC)
c’
d 7.11
d 7.12
d 7.12
R=Mc
R= Et
R=Pr
R=Mc
R= Et
R=Pr,
d 6.83
d 6<85
d 6-83
t 0.94
R=Me
R = Et
R-Et
d 7.65
d 7.60
d 7.10
d 7.10
R=Mc
R = EI
R=Me
R = Et
d 6.86
d 6.88
R=Mc
R = Et
(VIIO)
(Vllb)
(WC)
b\
c=c’Ii
b
R,5n’\coot)?,
LI
H’ ’ COOCH
c’
!I\
Cd
Cli,
c2
(IIIb)
(Illa)
DATA OI: COMPOUNDS (+(x)
R,5n-C_=C-COaCy4,
R,Sn-Clp2i,--COOCH
TABLE 1. NMR
DATA
OF COMPOUNDS
d 2.05
d 2.00
d 2.13
d 2.11
R=Mc
R=Bu
R=Mc
R=Bu
R=Me
R=Et
R = Bu
R=Me
(XVa)
(XVIb)
(XVIla)
(XVIlb)
(XVIIC)
(XVIIIn)
(XVIII)
W’b)
d 7.29
d 6.63
d 6.65
d 6.62
q 7.39
q 7.41
R=Me
R =Bu
(XIVa)
(XlVb)
d 6.18
d 6.10
d 6.06
d 6.04
q 6.34
q 6.36
q 6.24
q 6.18
d 1.90
d 1.86
b6.12
b 6.3
b6.12
b 6.3
R =Et
R = Ph
(XIHb)
(XIlIa)
14.7
2.6
2.6
2.7
1.7
1.6
6.9
7.0
7.0
7.0
3.2
<l.O
12.9
; 6.74
; 6.25
R = Ph
(XIlb)
5.0
<l.O
cl.0
Jbr
(112)
1205
:’ 6.65
:’ 5.94
R =Et
(XIla)
Cl.0
JPC
ccmfurrts
<l-O
coirplirrg
<LO
2.0
:’ 5.37
:’ 5.92
2.5
d
t 5.18
II = PI1
Jah
(ppm”).atd
i-r,
slrijls”
;5,86
6l
Chefnical
R = Et
(X+(xX1)
54.0
97.5
88.0
8885
118.0
108.0
-68
J(Sn-&)
56.0
102.0
92.0
92.5
123.0
112.5
106.5
51.5
44.0
44.5
61.5
-116
-109
111.5
54.0
46.0
46.5
64.5
(continued overleflf)
-70
-135
J (Sn-H,)
u Only multiplicitiesdue to H-H coupling are given; S: singlet; d: doublet ; t: triplet; q: quartet; b: unrcsolvcd broad signal. I’Downficjd from tctramethyjajlane
intcrnol. c Coupling constants with “‘Sn and ’ “Sn isotopes, respcclively.
_-__._
Conrpolrrlds
TARbE 2, NMR
..__..__
b
b4
(XIXn)
R==Me
R = Et
R= Bu
R=Mc
R = Et
R = Rn
R = I’ll
R=Mc
-_--
s 6.81
s 6.83
s 6.77
s 7,05
d ‘I,54
r,
s 5.97
s 5,94
s 5.92
d 5.75
fib
Cl~etnicul sl$fs” (pptn”)
20,4
Jnb
J ac
.._l_l
Jl,
arIdco~rplin~
cor~slnrrls
(IIz)
92.5
83.5
83.0
112.5
J&n-H,Y
97.0
87.5
87.0
117.0
58.0
50.0
49.5
J(h+&)
io.5
52.5
52.0
C1;&H7
k
;;
\
R,SJW’ \
\ CSN
0
ii’
NEC,c=c,Qf%
I
Conlpollrlds
TABLE 3. NMR DATA
R = ?t
(XXlIb)
(XXIVC) R = PI1
(XXIVb) R = Et
(XXlVa) R = MC
R = Me
(XXII)-(XXXIV)
(XXlIa)
01: COMPOUNDS
4
J nb
4
6.11
4 5.70
4 5.76
rf 6075
(f 6049
; 6,42
12,O
1245
12.5
s 6.47(in cyclohcxane)
butyronitrilc)
s 6.83(in hutyrdnitrile)
s 6.44
6.75 (in cycioliex;rne)
42
0.8
1.7
I.0
_..Jm
6.8
7.0
7.2
J be
CAenlico~
slqis” (pprr,“)and cofrplin~consronts
(Hz)
60.5
59.0
54.0
66.5
-92’?
-73
-82
63.0
61.0
56.0
69.5
* 176?
n 143
-154
J (h-t&,)
’ Only multiplicitiesdue to H-H couplingarc given; s: singlet;d: doublet; I: triplet; q: quartet; b : unresolvedbrondsignnl.’ Downfieldfrom tctramctbylsilanc
internnl.r Coupling constantswith “‘Sn nnd ’ ‘“Sn isolopcs,rcspcctivcly.
P
I,’
A,Sn
\&C/H
-_.-_.
Conpounds
TABLE 2 (cm/trued)
bh
.,m_
15.6
15.7
11.4
1.8,5
d 6.19
d 6.46
d 7.07
d 6.42
d 4.46
d 4.89
d 6.00
d 5.91
R = Et
R = Ph
R = Et
(XXXb)
(XXXla)
(XXXlb)
(XXXIIIa)
(XXXIVa) R = Et
I .
63.0
60.0
7.1
6.8
d 6.73
d 6.82
d 4.46
d 4,88
R = Et
R = Ph
(XXXa)
.a.._ .
62-5
59.5
1.8
-64
d 4.00
48.5
61.0
59.5
d 4.64
-70
-661
R = Et
46.5
58.0
57.0
(XXIXa)
13.6
13.7
13.4
58.0
122.0
121.0
97.0
61.0
127.5
101.5
126.0
N 148?
13285
138.0
-164
,”
n Only multiplicitiesdue to H-H coupling are given ; s: singlet; d : doublet; t : triplet; b : unresolved broad signal.* Downfield from tctnmcthylsilandinternnl.
H’
0
d 1.55
d 7.62
d 7.80
b 6.82
b 6.83
d 6.15
d 6015
d 6.43
-84
-73
-9O?
b 6.82
b 6.83
R = MC
R = EI
R = Ph
b 5.92
b 5.88
b 6.25
(XXVIIla) R = Me
(XXVIIIb) R = Et
(XXVlIn)
(XXVlIb)
(XXVlIc)
2-2 c Coupling constants with ‘I ‘Sn and “YSn isotopes, respcctlvcty.
g
tit
b
b
R3Sn\czc/H
0
b 5.92
b 5.88
b 6.25
E
Q
290
A. J. LBUSINK,
H. A. BUDDING,
J. W.
-N
differences between the chemical shifts, CA&,, of cis- and truns-olefinic protons as a
result of differential shielding by &substituents (see also ref. 3). These assignments
have now been confirmed by the magnitude ofthe observed coupling constants of the
oleftic protons with ll’Sn and rrgSn isotopes. In general it appears that :
is slightly larger than IJ(Sn-H&j,
while /J(Sn-H,,,,)I
is about two
(4 1J (Sri-H,,,,
times as large as I J(Sn-H,,)]
;
(b) the absolute values of these coupling constants are lowered by electron-withdrawing substituents at the double bond.
In Table 4 a survey is given of the results obtained in the hydrostannation of
monosubstituted ethynes. As appears From this Table hydrostannation of these
ethynes afforded both a- and fl-adducts:
R,SnH
+
H-C3C-R’
----)
l-4
\
/
SnR,
H/c=c\R,
+
H\
/ch(
R,Sn
cy
TABLE
R’
cis-j3
R&n
+
\
/
H
H
C=C’
\
R’
trans-,B
4
HYJXlOSTA?WATlON OF LIONOSUJS7’ITV’RD
Exp.
H
R
R
NO.
I”
Me
COOEt
20
3”
4”
5
Me
El
Pr
Et
COOMe
COOMe
COOMe
CH,OH
6
Ph
CH,OH
7
8
9
i0
II
Me
Et
Pr
Me
Et
CN
CN
CN
BU
Bu
12
13
14
Ph
Me
Et
BU
Ph
Ph
15
Ph
Ph
16
17
w
Et
Ph
Er
OEt
OEt
SBu
ETHYNES
Reaction
conditions
ish?
550
4 b
SO*
23 h, 55”
23 h
559
544
55”
6h, 100°
3h
60”
20°
t i6h,
1 I& 20”
1 h, 20°
1 h, 20”
74
60°
6 h, 50°
124
500
164
20°
3 4
500
66 h. 50°
74
60”
I 2 4
20°
i : 1 adducts
Total yield
4I %
40%
57%
72%
>70%
.
80 %
100%
100%
loo%
SS’?;
55%
Structures and ratio z/cis-/$&am-~
(Ia)~(IIa)/(IIIa) =
67:25:
8
(VIa)/(VIIa)/(VIJIa)
(VIb),‘(VIIb)/‘(VIIIb)
fvIc)/(vIIc)/(vIIIc)
(XIa)/(XIIa)/(XIIIa)
=
=
=
=
8l:l.S:
4
58:24:18
31:36:33
25~45~30
(XIbj/(XIIb)/(XIIIb)
=
5:45:50
(XVIIa)/(XVIIIa)/(XIXa)
(XVIIb)/(XVIIIb)/(XIXb)
(XVIIc)/fxvIIIc)/(xIxc)
(XkIIIa)@XIVa)~(kXVaj
(XXIIIb)/(XXIVb)/(XXVb)
= 100: 0 : 0
= 100 : 0 I 0
= loo : 0 I 0
=
2:29:69
=
3:51:46
zz
3:31:66
75%
(xxrIIc)!(xxrvc);(xxvc)
(XXVIa)!(xXVIIa)/(XXVIIIa)
(XXVib)/(XXVIIb)/(XXVIIIb)
=
=
=
0:85:15
6:66:28
0:70:30
(XXvIc)/(XXVrIc)/(XxvIIIc)
=
0:28:72
(~a)/(XXXa)/(XXXIa)
(XXIXb)/(XXXb)/(XXXIb)
@XXIIa)/(XXXIIIa)/(XXXIVa)
=
=
=
4:91:
5
0:97:
3
0:77:23
85%
1280%
75%
Ih
60”
90%
ljh
1h
3 h,
50°
20°
45O
100%
>90%
70%
a In these experiments also other products are formed, viz. (IV), (V}, (IX), (X) and 2: 1 adducts (see also
Table 1 and ret 2). b In the presence of butyronitrile.
j- Organomtal.
Chem, 9 (1967) 285-294
291
STUDIE!SIN GROUP IV ORGANOMETALLIC CHEMISTRY. XXIV
For a discussion of the structural assignments the reader is referred to previous
papersz-4. Experiments l- 5 and 7-9 have been described before. In the latter experiments exclusively the a-adduct is formed. Detectable amounts of the cis- and trans8-adducts (XVIII) and (XIX) are formed under special conditions only4, viz. in the
presence of both an apolar solvent (retardation of the rate of formation of the CLadduct) and a free radical initiator (acceleration of the rate of formation of the
/3-adducts). The gas chromatograms of the reaction mixtures obtained in experiments 10,ll and 13 displayed three peaks, which obviously arise from 1: 1 adducts.
As appeared from NMR data the two main peaks are due to the cis-j?- and bans+adducts. The small third peak was assigned to the a-adduct. The correctness of this
assignment could not be verified by NMR spectroscopy as a result of the low concentration of this isomer in the NMR samples. In experiment 14 only two peaks
arising from 1: 1 adducts (cis- and trans-@-adduct) were observed in the gas chromatogram. However, this does not exclude the presence of a very small amount of the
or-adduct, which might have escaped detection by NMR spectroscopy as well. Similarly, in the NMR spectra of the reaction mixtures from triphenyltin hydride and
1-hexyne (exp. 12) and ethoxyethyne (exp. 17) and from triethyltin hydride and butylthioethyne (exp. 18) only signals due to the #Ladducts could be detected, but also in
these cases very small amounts of the a-adducts may be present. In the NMR spectrum
of the reaction mixture from triphenyltin hydride and phenylethyne (exp. 15) the
olefinic protons of the trans-&adduct are obscured by the phenyl signal. Since
approximately 90% of the ethyne had reacted yielding 25 y0 of the cis+adduct
(XXVIIc), it was concluded that about 65 % of the trans+adduct
(XXVIIc) had been
formed. A pure sample of the latter adduct was isolated from the reaction mixture.
As has been reported before3 at last three 1: 1 adducts were formed in the
hydrostannation of ethyl 1-propynecarboxylate. Two of these adducts appeared to
be the isomeric a-adducts (XIV) and (XV). In view of the fact that mainly transaddition occurred in this type of additions structure (XVI) was tentatively assigned
to the third adduct.
R,SnH
+
Me-CrC-COOEt
Me
----*
-+
H
SnR,
\
-I-
C=C
l-l’
/
’ CooEt
\
+
C=C’
COOEt
\
R,Sn
xp
R = Me; (XIVb)-(XVIb),
H
C=C’
/
\
Me
xm
(XIVa)-(XVIa),
Me
SnR,
\
COO!3
XSD
R = Bu ; (XIVa)/(XVa)/(XVIa)
(XIVb)/(XVb)/(XVIb)
= 59 : 9 : 32
= 50 : 13 : 37
The correctness of this assignment has now been proven by the trans-coupling of the
olefinic proton of (XVI) with “‘Sn and llgSn isotopes. Similarly, the assignment of
structures (XX) and (XXI) [(xX)/(xX1) M 9 : 11 to the adducts formed in quantitative
EtOOC
SnR,
R,SnH
f
EtOOC-CrC-COOEt
+
(XXa)-(xxIa),
R = Me; (XXb)-(XXIb),
+
C=C{
Hi
cool3
R = E?(XXc)-(XXIc),
SnR,
H
\
\
WC<
Etooc’
COOEt
XXI
R = Bu
J. Organometal. Chem., 9
(1967) 285-294
A. J. LEUSINK,
292
H. A. BUDDING,
J. W. MARSMAN
yield in the reaction of trialkyhin hydrides with diethyl ethynedicarboxylate has now
been proven by the ’ 17*11gSn-H01ef. coupling constants of both (XX) and (XXI).
Incidentally, very small amounts of diethyl fumarate were found to be present
in the reaction mixtures. Most probably diethyl fumarate is formed by disproportionation of the primary adducts*, P.+ :
EtOOC
2
\
H’
c=c
/
EtOOC
SnR,
‘COOEt
\
,C=C’
H
-
H
\
EtOOC
STlR,
+
COOEt
R,Sn
COOEt
Addition of triphenyhin hydride to the diethyl ethynedicarboxylate
at 20”
in the presence of solvents (cyclohexane or butyronitrile) afforded mixtures in which
adduct (XXd) and diethyl fumarate were present in a ratio of approximately 5 : 1. The
yield calculated on the amount of hydride consumed (85 % in butyronitrile and 70 %
in cyclohexane) was quantitative, assumin g that diethyl fumarate is formed by
disproportionation of the 1: 1 adduct.
Hydrostannation of dicyanoethyne in the presence of the same solvents as
above afforded one adduct (singlet in the olefinic region) in more than 80% yield.
N=_C
R&%-i
+
NsC-CEC-CZN
3
H
(XXIIa),
R = Me; (XXIIb),
\
/
c=c
/
\
SnR,
C=N
R = Et
The assignment of structure (XXII) to this adduct is based on the magnitude of
the coupling constants of the oleflnic proton with the “‘Sn and “‘Sn isotopes
(-60 Hz).
As mentioned above the absolute values of the L17P11gSn-%101rLcoupling
constants are lowered by the presence of eIectron-withdrawing groups at the double
bond. Since J,,, and 3,, in a compound like (XVIIIb) with one cyan0 group attached
to the doubIe bond, have been found to be 90 and 45 Hz, it must be expected that in
compound (XXIIb) and its isomer J,,,, and J,i, are much lower than 90 and 45 Hz,
respectively. Consequently, it must be concluded that compound (XXII) is the main
product in this type of reaction. The presence of its isomer could not be detected_
Furthermore, the NMR spec.ra revealed the presence of very small amounts of 1,2dicyanoethene, which might have been formed by disproportionation
of the 1: 1
adduct (see above)_
CONCLUSIONS
The experiments described above demonstrate that in reactions of organotin
monohydrides with ethynes in general a mixture of products is formed. Apart from
* Similar disproportionationshave been observedGth adducts from triethyltin hydride and diethyl
azodicarboxyiate5 and from triphenylplumbyllithium and diethyl ethynedicarboxylate6, while attempts to
distill the adduct from trimethyilead hydride and diethyl ethynedicarboxylate (diethyl trimethylplumbylfumarate) resulted in the formation of diethyl fumarate and unidentified materials’.
J. Orgauometal. Chem, 9 (1967) 285-294
Sl-UDES IN GROUP IV ORGANOMETALLIC CHEMISTRY. XXIV
293
the formation of 2 : 1 adducts and of some other products in the case of ethynemonocarboxylates it appears that :
(4 addition of trialkyltin hydrides to monosubstituted ethynes containing a strongly
electron-withdrawing
substituent (COOR, C=N) affords mainly, or even exclusively, the cr-adduct ;
@Iaddition of organotin monohydrides to monosubstituted ethynes containing an
electron-releasing (C,Hg, OC2H5) or a weakly electron-withdrawing (CH,OH,
C6H5) substituent affords mainly the cis- and trans-j3-adducts, in addition to
small amounts of the cr-adduct ;
(4 addition of trialkyltin hydrides to disubstituted ethynes affords mainly the
truns-addition products.
As may be derived from the experiments involving ethyl 1-propynecarboxylate
_
_
__
and I-hexyne the cis-xc- as well as the cis-p-adduct seems to be the prrmary adduct
(occurrence of &runs-addition), which is in accord with similar observations in the
case of phenylethyne’.
Non-terminal addition (formation of a-adducts) although of minor importance
in some of these hydrostannations, has been observed in almost all cases studied_
Consequently, the generally accepted rule of exclusive terminal addition does not
hold true for additions to carbon-carbon
triple bonds. Formation of considerable
amounts of the cr-adduct can hardly be explained in terms of the free-radical mechanism proposed for these additions ‘. Therefore, a closer study of the mechanistic
aspects of the reactions leading to the several 1: 1 adducts was made, the results of
which will be presented in subsequent papers.
EXPERIMENTALPART
All reactions and subsequent manipulations were carried out in an atmosphere
of dry, oxygen-free nitrogen. L iquids were handled by the syringe technique.
Starting materials were purchased or prepared according to published
procedures. Solvents were carefully purified and dried by conventional methods. All
liquid materials were distilled before use in an atmosphere of nitrogen either at
normal or at reduced pressure_
NMR spectra, which were run by Mr. M. J. A. de Bie (Laboratory of Organic
Chemistry, State University of Utrecht) and Miss L. Veldstra, were recorded using a
Varian Associates A-60 NMR spectrometer * and a Varian Associates HR-1OOA
NMR spectrometer. In most of the NMR experiments carbon tetrachloride was used
as a solvent (30430 o/0by volume). Experiments in this solvent, in which the concentration of the solute [for this purpose a mixture of compounds (Via) and (VIIa), compare
Table 11 was varied from 10 74 to 80 ‘A (by volume), revealed that within this concentration range the chemical shifts are not a function of the concentration.
IR spectra, which were run by Miss G. E. E. Woldringh, Miss L. Veldstra and
Miss H. Alberda, were recorded using a Perkin-Ehner
spectrophotometer
type
Infracord 137 and a Grubb Parsons Spectromaster.
Gas-chromatographic
analyses were made by means of F & M Gas Chro* The authors are much indebted to Professor J. F. Arens (Laboratory of Organic Chemistry, State University of Utrechtf for making available the 60 MHz NMR spectrometer.
J. OrganomeraL
Chem, 9 (1967) 285-294
294
A. J. LEUSINK,
H. A. BUDDING,
J. W.
MARSMAN
matographs Models 500 and 810 with katharometer detection, using helium as a
carrier gas. In these analyses, which were performed by Miss G. G. de Haan, carbowax
and silicone oil columns have been used (see also ref. 2,3 and 4).
As an example of the procedure followed experiment 11 has been described
below*.
Addition of triethyltin hydride to I-hexyne (exp. 11)
A mixture of 2.3 g (11.1 mmoles) of triethyltin hydride and 1.0 g (12.2 mmoles)
of I-hexyne was heated at 50° for 6 h. Samples were taken from this mixture and
analyzed by means of GLC( - 55 oAconversion after 6 h)_ The reaction mixture was
left overnight at room temperature and-heated at 50° for an additional period of 6 h
tconversion - 85 %)_ As appeared from the gas chromatograms the amount of adduct
(XXIVb) remained almost constant after the first heating period, whereas the amount
of adduct (XXVb) increased steadily.
Distillation afforded 2.3 g (72% yield) of a mixture of 1: 1 adducts, boiling
at 52-58O/O_O6
mm, n&O1.4822.(Found: Sn 41.2. C,,H,$n
calcd. : Sn 41.06%_)
ACKNOWLFZDGEMENT
The authors are much indebted to Professor G. J. M. VAN DER KERK for his
stimulating interest and to Dr. J. G. NOLTJZSand Dr. W. DRENTH for discussions.
Part of this work was sponsored by the International Tin Research Council. The
authors are indebted to Dr. E. S. HEDGB for permission to publish.
Organotin monohydrides were brought into reaction with a variety of monoand disubstituted ethynes. The identity of the resulting products was established by
mean&of elementary analysis, infrared absorption spectroscopy and proton magnetic
resonance spectroscopy.
In the hydrostannation of monosubstituted ethynes both OL-and j?-adducts
are formed. Electron-withdrawing substituents favour the formation of a-adducts.
In the formation of the /Ladducts,as well as in the hydrostannation of disubstituted
ethynes, trans-addition seems to be the rule.
REFERENCES
1 H. M. J. C_ C-,
F. VERBEEKAND J. G. NOL-ZS, J. Organometal. Chem., 8 (1967) 469.
2 A. J. LEUS~T. J. W. MARS~~AN,H. A. BUDDING, J. G. No~-rrs AND G. J. M. VAN DER KEXK, Rec. Trav.
Chim., 84 (1965) 567.
3 A. J. LEUS~K, J. W. M&S%tAN AND H. A. BUDDING, Rec. Trav. Chim., 84 (1965) 689.
4 A. J. LEUSIXK, Ph.D. thesis, State Uriveti.ty of Utrecht, The Netherlands, 1966.
5 J. G. NOLTES, Rec. Tmv. Chim., 83 (1964) 515.
6 L. C. WILIB~ENS,
personal
communication_
7 k J. LEusrnx, unpublished results.
8 R. F_ FULT~N. PbD. thesis, Purdue University. 1960.
9 W. P. NEUMANN ANI) R So-,
Ann. Chem., 675 (1964) 10.
* For additional data see ref. 4.
J. Organometd. Chem.. 9 (1967) 285-294