Mini-Reviews in Organic Chemistry, 2008, 5, 303-312
303
Metal-Catalyzed Cross-Coupling Reactions for Ferrocene Functionalization: Recent
Applications in Synthesis, Material Science and Asymmetric Catalysis
V. Mamane*
Laboratoire SRSMC, Equipe Synthèse Organométallique et Réactivité, UMR CNRS-UHP 7565, Faculté des Sciences et Techniques,
Nancy-Université, BP 239, 54506 Vandoeuvre-Lès-Nancy, France
Abstract: Recent examples on the functionalization of the ferrocene core by means of cross-coupling reactions are reported in this review. Several methods are discussed including Negishi, Suzuki and Stille couplings for ferrocene-aryl bond formation and Sonogashira
reaction for ferrocene-alkyne coupling. The properties in material science and asymmetric catalysis of the prepared ferrocenyl compounds are briefly discussed.
Keywords: Cross-coupling, palladium, ferrocene, material chemistry, asymmetric catalysis.
1. INTRODUCTION
Due to its interesting inherent electrochemical properties and to
its planar chirality, 1,2 or 1,3-disubstituted ferrocene has found a
wide application in material science [1] and in homogeneous (asymmetric) catalysis [2]. Therefore, several methods to introduce substituents on the cyclopentadienyl (Cp) rings of ferrocene, have been
developed. Among these methods, metal-catalyzed cross-coupling
reactions [3] have become a powerful tool to achieve highly efficient
and selective transformations on one or both Cp rings. This review
will focus on recent examples employing cross-coupling reactions to
create C-C and C-Heteroatom bonds directly on the ferrocene core.
2. FERROCENE-ARYLE BOND FORMATION
A recent study on the synthesis of nonracemic C2-symmetric 1,1’binapht-2,2’-yl bridged ferrocene (1) was reported by Kasak and
colleagues [4]. For this purpose, they used several palladiumcatalyzed reactions to couple enantiopure 2,2’-diiodo-1,1’-binaphtyl
(2) with 1,1’-dimetalloferrocenes (3), including the Negishi [5], Suzuki [6] and Stille [7] cross-couplings. The Negishi protocol gave the
desired product with the highest yield and with stereoconservation,
whereas Suzuki and Stille reactions led to complete racemization of
binaphthyl moiety (Fig. (1)).
M
I
Pd
+
I
Fe
conditions
M
(3)
(2) 95% ee
M
yield (%)
ee (%)
ZnCl
35
95
12
0
11
0
O
Fe
B
O
(1)
SnMe3
Fig. (1).
These results explain the fact that the Negishi cross-coupling reaction has found numerous applications. However, during the last
*Address correspondence to this author at the Laboratoire SRSMC, Equipe Synthèse
Organométallique et Réactivité, UMR CNRS-UHP 7565, Faculté des Sciences et
Techniques, Nancy-Université, BP 239, 54506 Vandoeuvre-Lès-Nancy, France;
E-mail: [email protected]
1570-193X/08 $55.00+.00
decade, the Suzuki coupling has gained in interest due to the facile
access to the boronic species. The use of the Stille coupling is still
limited, particularly due to its strong sensitivity to steric hindrance.
2.1. Negishi Coupling
The ferrocenylzinc intermediate necessary for the cross-coupling
is generated by transmetallation of the lithio derivative, which can be
obtained by direct lithiation of ferrocene [8], by directed orthometallation (DoM) [9] or by halogen-lithium exchange [10]. In early studies, PdCl2(dppf) (dppf = diphenylphosphinoferrocene) was described
as the best catalyst to perform the Negishi coupling but it has been
shown later that Pd(PPh3)4 and more interestingly PdCl2(PPh3)2 were
good catalysts for this reaction. The first example was reported in
1985 by Rosenblum’s group for the synthesis of cofacial ferrocenes
[11]. Among several mono-metallated ferrocenes tested in the crosscoupling with 1,8-diiodonaphtalene (4), the ferrocenylzinc intermediate led to the best results with formation of the bis-coupled product
(5) in good yield in presence of PdCl2(dppf) as the catalyst. If one of
the two ferrocenes is replaced by a Cp group such as in (6), face-toface metallocene triads (7) [12] and polar cofacially fixed sandwich
complexes (8) for Second Harmonic Generation (SHG) [13] could be
prepared. While a “through space” interaction exists no SHG intensity could be observed (Fig. (2)).
Interferrocenic communication in molecules having two or more
redox centers is fundamentally interesting for the study of multielectron transfer processes via mixed valence state derived from these
multi-metallic systems [14]. In this field, the Negishi cross-coupling
has been widely used to install two or several ferrocene moities
around different scaffolds. Two ferrocene fragments could be introduced by Ogawa and colleagues on thianthrene, leading to a new type
of multi-steps reversible redox organic-organometallic hybrid molecule (9) [15]. Vollhardt’s group has succeeded in the introduction of
five ferrocene units around the Cp ring in [(C5H4)Mn(CO)3] to give
(10) [16] and six ferrocene units around a benzene ring to furnish
(11), albeit in poor yield [17]. These new multinuclear ferrocenic
compounds are of potential interest since their architecture apparently
allows for considerable electronic interaction (Fig (3)).
Another family of highly symmetric hexaferrocenyl complexes
(12) was previously described by Mamane and colleagues [18, 19].
These compounds having six chiral ferrocene units around a hexaarylbenzene core were prepared by a [2+2+2] cyclotrimerization
reaction of the corresponding alkyne monomer (13), itself obtained
by a double Negishi coupling of chiral ferrocenylzinc (14) intermediate with bis-(p-bromophenyl)acetylene (15). Intermediate (14) was
used by the same group for the design of new C3 symmetric chiral
architectures (16) bearing organometallic donor-acceptor fragments
[20]. These octupoles possessing good SHG properties showed a
significant electronic interaction between the three 1-D arms through
the benzene ring (Fig. (4)).
© 2008 Bentham Science Publishers Ltd.
304 Mini-Reviews in Organic Chemistry, 2008, Vol. 5, No. 4
I
V. Mamane
I
Fe
M
Fe
I
CpZnCl
Pd
FcZnCl
Pd
(4)
FcZnCl
Pd
Fe
63-76%
58%
M = Fe, Co+, TiCl2
(7)
+
Me5
Fe
Fe
Fe
M
PF6(6)
(8)
(5)
M = Fe, Rh, Ir
Fig. (2).
Fe
Fe
Fe
Fe
Fe
S
Fe
Mn
S
Fe
OC CO CO
(9) 71%
Fe
(10) 60%
Fe
Fe
Fe
Fe
Fe
(11) 4%
Fig. (3).
O
1)
O
ZnCl
OMe
Fe
Br
Pd cat
Fe
(15)
Fe
2) Hydrolysis
(14)
CHO
Br
OHC
(13)
72%
Co2(CO)8
1) 1,3,5-Tribromobenzene, Pd
2) Hydrolysis
85%
Fe
59%
CHO
Fe
CHO
Fe
Fe
CHO
CHO
CHO
Fe
Fe
OHC
Octupoles with high second
order hyperpolarisabilities
CHO
Fe
Fe
OHC
(16)
OHC
Fig. (4).
Fe
(12)
Metal-Catalyzed Cross-Coupling Reactions
Mini-Reviews in Organic Chemistry, 2008, Vol. 5, No. 4
N
Fe
N
R
N
N
N
Fe
N
R=H
77%
R = 8-quinolyl 62%
(17)
N
N
Fe
N
Fe
N
44%
(18)
(19)
28%
(20)
N
Fe
25%
(21)
38%
N
N
N
N
N
N
N
N
N
N
N
305
(22)
Fe
20%
(23)
Fe
26% (enantiomer : 18%)
O
1)
O
ZnCl
CHO
N
, Pd
Fe
Fe
Fe
2) Hydrolysis
(26)
N
Aldolisationcrotonisation
N
Br
(25)
(24)
60-72%
Ferroceno-(iso)quinolines
Fig. (5).
Several nitrogen-containing heterocycles has been used as the
coupling partner of ferrocene in the Negishi cross-coupling reaction.
Enders and colleagues described the reaction of the quinolyl group at
the 8-position with ferrocene [21]. The coupling could be realized in
good yields once or twice for furnishing compound (17) which
showed interesting coordination behavior. In the same field, Mochida’s group designed several ferrocene-containing ligands (18)-(21)
by coupling pyrazines, pyrimidines and phenylazoles with the ferrocenylzinc complex under palladium catalysis [22, 23, 24]. Chiral
ligands (22) and (23) with ferrocene bridging units for chiral induction in self-assembled helicates were described by Quinodoz and
colleagues [25]. During their study, they compared the Suzuki and the
O
S
Fe
Tol
(27)
Tol
Ar
Zn
1) LDA
2) ZnX2
S
Ar
Ferrocene-based phosphine ligands are widely used in asymmetric catalysis, and during the last decade cross-coupling reactions allowed the synthesis of new families of arylphosphinoferrocenes. The
Negishi coupling was then used with success by several groups in
X
O
Fe
Negishi reactions for performing the bis-coupling of 1,1’dimetalloferrocene (3) with chiral bipiridines. The Negishi crosscoupling gave the best results although the yields were moderate in
all cases. In their synthesis of new chiral ferroceno-(iso)quinolines
(24) as potential molecules in asymmetric catalysis and material
chemistry, Mamane and Fort used different picolines (25) in the coupling reaction with racemic (26) or enantiopure ferrocenylacetal (14)
in good yields [26] (Fig. (5)).
Fe
S
ArX, Pd
S
Ar
O
O
PPh2
Tol
Fe
Tol
Fe
N
Ar = Ph
3,5-CF3-C6H3
o-MeO-C6H4
p-MeO-C6H4
1-Naphtyl
77%
60%
90%
95%
88%
N
Ph2P
O
O
S
Fe
(28)
R'
Tol
(29)
78%
75%
OAc SOTol
O
S
Fe
Tol
(31)
Fig. (6).
R = H, MeO, Ac, Bn
R' = H, t-Bu
Fe SOTol
Fe
63-92%
HO
(32) 41%
S
Tol
Fe
OR
RO
O
S
Fe
Tol
(30) 74%
306 Mini-Reviews in Organic Chemistry, 2008, Vol. 5, No. 4
V. Mamane
O
CHO
Fe
OMe
Fe
Suzuki : 100%
Negishi : 65%
(33)
(34) 91%
O
S
S
R
N
R
Fe
hexyl
Fe
S
N
R
hexyl
(35)
N
(36)
hexyl
R=H
38%
R = phenothiazinyl 54%
R=H
28%
R = phenothiazinyl 20%
R = Ferrocene
36%
Fig. (7).
SPh
SPh
SPh
Fe
Fe
Fe
NMe2
Fe
NMe2
(38)
(37)
Fe
35%
(39) 27%
33%
SPh
Fe
B(OH)2
Ph
N
N
Ph
N
Excess
porphyrin
B(OH)2
N
Zn
+
Ph
order to introduce an aryle group in -position of a chiral sulfoxide
which served as a directing group and could be easily transformed to
a diphenylphosphine group. Pedersen and Johannsen described the
synthesis of compounds (27), leading after transformation to monophosphine ligands which showed high catalytic activities in hydrosilylation of styrene [27]. Starting from derivatives (28)-(30),
Knochel’s group reported the use of diphosphines and aminophosphines in palladium-catalyzed allylic alkylation and amination
[28, 29]. The sulfoxide group can be maintained in the molecule as
described by Bäckvall’s group in the synthesis of a new class of
chiral ferrocene-based quinone ligands (31) and (32). Most of the
ligands decomposed during the deprotection of the OR groups except
for one (R’ = R = H in (31)) and a poor enantioselectivity was obtained when used in the asymmetric diacetoxylation of cyclohexadiene [30] (Fig. (6)).
2.2. Suzuki Coupling
The Pd-catalyzed cross-coupling reaction between halobenzenes
and ferrocene-1,1'-diboronic acid was reported for the first time by
Knapp and Rahahn [31]. 1,1'-Diphenyl- and 1,1'-bis(halophenyl)substituted ferrocenes bearing fluoro, chloro and bromo substituents
N
P
h
N
N
Ph
Ph
N
(43) 14%
18%
Fig. (8).
N
N
Zn
Ph
N
Zn
OTf
N
(42)
Ph
(40)
Fe
Excess
boronic acid
(41)
Ph
were obtained in good yields. In 1999, Imrie and colleagues reported
a systematic study on the use of Suzuki reaction for the synthesis of
monoarylferrocenes from haloferrocenes and arylboronic acids [32].
They found that the use of strong bases such as barium hydroxide or
potassium carbonate in the presence of Pd(OAc)2 as a catalyst was
necessary to achieve good conversions. These conditions were later
utilized by different groups for the synthesis of ferrocene-containing
molecules of potential interest in material chemistry. Mamane and
Riant obtained an excellent yield of aldehyde (33) in the coupling of a
chiral iodoferrocene compound with p-methoxyphenylboronic acid
showing that this method is a good alternative to the Negishi coupling
[33]. Butler and colleagues generated ferrocenylanthraquinone compound (34) in good yield by changing the catalyst to Pd(PPh3)4 [34].
Recently, Sailer and colleagues described several ferrocenephenothiazine systems (35) and (36) with interesting electronic properties [35] (Fig. (7)).
Other methods involving ferroceneboronic acids have been used
to perform the Suzuki reaction. Hua and colleagues described the
coupling between 2,4,6-tris(1’-phenylthio-1-ferrocenyl)boroxin and
1,8-diio-donaphtalene to give (37) or 1,8-diidobinaphtyl to yield (38)
in presence of Pd(PPh3)4/NaOH system in moderate yields [36]. With
Metal-Catalyzed Cross-Coupling Reactions
R
NaOH, MW
KOH/Al2O3
R = B(OH)2
N
Fe
Mini-Reviews in Organic Chemistry, 2008, Vol. 5, No. 4
R = 4-pyridyl NaOH, Reflux 53%
KOH/Al2O3
30%
R = 5-pyrimidyl KOH-KF/Al2O3 20%
(44)
N
N
Fe
R
57%
57%
R = B(OH)2
R = 5-pyrimidyl
KF/Al2O3
40%
KOH/Al2O3 32%
(45)
Fe
SMe
FcB(OH)2
N
F
N
B
CuTc, [Pd2(dba)3, TFP]cat
F
N
F
98%
N
B
F
(46)
Fig. (9).
PdCl2(dppf)/NaOH system, Köcher and colleagues obtained a low
yield of (39) by coupling 3,5-(dimethylamino)methyl iodobenzene
with ferrocene. Compound (39) was then used for NCN pincer complexes synthesis [37]. Ba(OH)2 was used as the base by Cammidge
and colleagues for the synthesis of face-to-face porphyrin-ferrocene
systems [38]. It has been shown that changing the ratio between 1,1’ferrocene diboronic acid (40) and porphyrin (41) modified the reaction pathway. While excess boronic acid delivered the ferroceneporphyrin dyad (42) with loss of one boronic acid group, excess porphyrin yielded an unexpected product (43) resulting from the intramolecular cyclization with no incorporation of ferrocene (Fig. (8)).
The Suzuki reaction has been applied to the coupling of several
heterocycles with ferrocene mono- or di-boronic acid. During its
work on molecular crystal engineering involving organometallics
building blocks, Braga’s group described the synthesis of pyridine
and pyrimidine ferrocenyl derivatives (44) and (45). Methods such as
microwaves [39] or KF/alumina [40] in the presence of PdCl2(dppf)
as the catalyst were used for the selective preparation of mono-,
homo-bis and hetero-bis-functionalized ferrocene starting from 1,1’ferrocene diboronic acid (40). A very efficient method for Bodipy
functionalization involving a thiomethyl group in the cross-coupling
with boronic acids was reported recently by Pena-Cabrera and colleagues [41]. Bodipy (46) incorporating ferrocene in 8-position could
be prepared by this method with an excellent yield (Fig. (9)).
307
A number of chiral ferrocenyl ligands having an aryle group directly attached to one or both Cp rings were developed during the last
years. Laufer and colleagues described the synthesis and application
in asymmetric diethylzinc addition to benzaldehyde of a C2symmetric planar chiral ferrocene diamide (47) [42]. Although the
yield of the coupling was low, the ligand was obtained with unchanged ee (enantiomeric excess) comparing to the starting material.
A similar ligand was prepared in a better yield by the Stille coupling
but the ee was not determined. Johannsen’s group improved its own
synthesis of aryl-ferrocenyl phosphines by using the Suzuki coupling
instead of the Negishi protocol [43]. The new conditions using a
chiral ferrocene boronic acid allowed the formation of compounds
(48) containing free amino and hydroxyl groups. Anderson and colleagues reported the preparation and evaluation of ferrocenyloxazoline palladacycle catalysts derived from ligands (49) in catalytic
asymmetric synthesis of chiral allylic amines [44]. A new class of
ferrocenylphosphines (50) was prepared by Stead and Xiao starting
from ferrocene diboronic acid (40) and bromoarenes bearing a
diphenylphosphine oxide group [45]. A subsequent reduction in presence of HSiCl3 yielded the free phosphines. A series of precursor
phosphine ligands (51) containing aryl groups was recently obtained
in high yields by Wang and colleagues [46]. After transformation to
1,2,3-trisubstitued ferrocenyl diphos-phines (52) containing a phenyl
or a xylyl group, these ligands were compared to other known
phosphines in asymmetric hydrogenations (Fig. (10)).
2.3. Stille Coupling
Ma’s groups reported the synthesis of a variety of heteroaryl ferrocenes by using the Stille cross-coupling. In presence of
PdCl2(PPh3)2 as the catalyst, tributylstannylferrocene and electronpoor heteroaryls gave the desired coupling products (53)-(58) with
good yields. Less electron-poor substrates required the use of
Pd(PPh3)4/CuO system to achieve good conversions [47]. With 1,1’bis (tributylstannyl)ferrocene (59), only electron-poor heterocycles
were described to perform efficient stepwise coupling to give (60)
and (61) respectively [48]. The intermediary 1-tributylstannyl, 1’heteroaryl ferrocenes (60) were also homocoupled in presence of
copper to yield bis(heterocyclyl)biferrocene compounds (62) [49]
(Fig. (11)).
In order to perform the cross-coupling between electron-rich and
sterically demanding partners, methods involving ligands such as
AsPh3 or Pt-Bu3 were recently described. Song and colleagues used
AsPh3 as ligand for palladium to prepare pyrimidine nucleosides (63)
incorporating a ferrocene moiety as a redox probe to study the electron transfer in DNA [50]. The same catalyst system was recently
OMe
MeO
R
CON(i-Pr)2
SO-p-Tol
Fe
Fe
CON(i-Pr)2
(47)
(48)
20%
R = Br
R=I
R = OH
R = OMe
R = OBn
R = NH2
R = NHAc
R = NO2
POPh2
54%
45%
50%
69%
49%
33%
85%
78%
Ar
O
POPh2
t-Bu
(49)
PPh2
Ph
HSiCl3
Fe
N
Fe
N
PPh2
Fig. (10).
(50)
PR2
O
PPh2
Fe
Fe
3-position : 54%
4-position : 78%
84%
88%
33%
20%
92%
85%
83%
76%
Ar
Ar
Fe
R = Ph
R = 4-MeOC6H4
R = 4-CF3C6H4
R = 2,6-(MeO)2C6H4
R = 1-C10H7
R = 2-MeC6H4
R = 2-MeOC6H4
R = 4-MeSC6H4
Ar = Ph
Ar = Xyl
(51)
51%
80%
(52)
308 Mini-Reviews in Organic Chemistry, 2008, Vol. 5, No. 4
V. Mamane
R2
R1
N
Fe
R1 = Me, R2 = NO2
R1 = NO2, R2 = Me
R1 = MeO, R2 = NO2
R1 = NO2, R2 = MeO
R1 = Cl, R2 = NO2
Ph
89%
91%
87%
85%
80%
O
N
N
Fe
R
(56)
R
S
Fe
R
(57)
Fe
SnBu3
R=H
5-NO2
5-COCH3
5-COPh
5-CO-pNO2C6H4
80%
95%
89%
90%
56%
N
N
Fe
HetAr1
Fe
S
Fe
R3
R3 = COCH3 75%
R3 = COPh 65%
From 2-nitropyridine
R3 = COCH3 60%
From 6-methyl-8-nitroquinoline
R3 = COPh 80 %
(61)
45-96%
S
R3 = COCH3 65%
From 8-methyl-6-nitroquinoline
R3 = COPh 78 %
R3
HetAr2
(62)
(58)
R3 = COCH3 75%
R3 = COPh 81%
HetAr2
HetAr1
R=H
90%
R = COMe 78%
R = COPh 36%
Fe
R1 = Me, R2 = NO2 85%
R1 = NO2, R2 = Me 83%
R1
70%
(60)
Ar1Het
S
R2
O2N
SnBu3
(59)
89%
(55)
95%
HetAr1
Fe
Ph
CO2Et
HetAr1
SnBu3
N
Fe
(54)
95%
85%
96%
93%
56%
90%
0%
0%
O
Fe
(53)
2-N, R = H
3-N, R = H
3-N, 6-NO2
3-N, 6-NHAc
3-N, 5-Br
3-N, 5-NO2, 6-NH2
3-N, 5-NH2
3-N, 5,6-NH2
Ph
Fig. (11).
used by Weber and colleagues for the synthesis of 1,2-disubstituted
planar-chiral ferrocene ligands (64) [51]. The Pt-Bu3 ligand was
shown to allow an efficient cross-coupling reaction between tributyl-
of ferrocenyl aryl products (67)-(69) in good yields [54]. A nickelassisted intramolecular coupling was used to perform the synthesis of
N
O
Fe
Fe
HN
Fe
O
O
N
N
Fe
HO
O
O
(63) 95%
O
(66)
R = Et
R = Br
O
80%
5%
O
(70) 47%
Het
Fe
N
(65)
Fe
76%
Ph
(71) 45%
(64)
74% (racemic)
OH
N
Fe
R
Fe
Fe
Fe
R
(67)
14 examples (60-97%)
(68) 92%
(69)
3-pyridine 84%
2-thiophene 90%
Fig. (13).
Fig. (12).
stannylferrocene and a bromopyridine containing the 2,5-dimethyl
pyrollidine group to furnish (65) [52] (Fig. (12)).
new chiral aryl-ferrocenyl ligands (70) [55]. A cobalt-catalyzed crosscoupling reaction involving a ferrocenyl cuprate formed in situ was
recently described to give (71) [56] (Fig. (13)).
2.4. Miscellaneous
3. OTHER FERROCENE-CARBON BOND FORMATION
Ferrocenyl pyridines (66) were prepared in good yields by using
the nickel-catalyzed Kumada coupling between ferrocenyl Grignard
intermediates and 4-bromopyridine [53]. The mono-coupling of 1,1’dibromoferrocene was not selective and furnished the desired compound in a poor yield. Bis(ferrocenyl)mercury reagents were coupled
with aryl iodides in presence of a palladium catalyst to give a variety
3.1. Ferrocene-Alkyne Bond: the Sonogashira Reaction
The triple bond spacer is widely used in ferrocene-based materials because it allows a good electronic communication between the
ferrocene unit and other electro-active groups. In this regard, the
Sonogashira reaction is the method of choice to couple alkynes and
iodoferrocenes [57].
Metal-Catalyzed Cross-Coupling Reactions
Mini-Reviews in Organic Chemistry, 2008, Vol. 5, No. 4
309
OMe
OMe
Si(i-Pr)3
OMe
Fe
MeO
Fe
Fe
Fe
MeO
(i-Pr)3Si
(72)
(73)
MeO
28%
OMe
Fe
Lidner and coll. : 55%
Engtrakul and Sita : 42%
Fe
MeO
t-BuS
St-Bu
(74) 26%
NMe2
Me2N
Pc
Fe
Fe
NMe2
I
Pc = Phthalocyanine
Me2N
(75)
(76) 48%
9%
Fig. (14).
SiMe3
Fe
Fe
Fe
Co2(CO)8
2nd
Me
Cobalt complexes
Me3Si
1st
(77)
Me
Co2(CO)8
Me Me
CHO
OH
S
Fe
n = 0, 1
n = 0 1st step: 25%; 2nd step: 23%
n = 1 1st step: 11%; 2nd step: 22%
OH
Fe
Me
S
Me
CH2
n
(78)
Co2(CO)8
OH
Fe
Me Me
70%
HO
Fe
(79)
(80)
2-CHO, (RFc) : 70% ; 2-CHO, (SFc) : 77%
3-CHO, (RFc) : 90% ; 2-CHO, (SFc) : 60%
Me
Co2(CO)8
Me
Fig. (15).
Plenio and colleagues described the synthesis of several optically
and redox-active ferroceneacetylene polymers and oligomers such as
derivative (72) [58]. While the reaction is high yielding with 1-iodo,
2-substituted ferrocene derivatives, the yield dropped when using
1,1’-dioodoferrocene. The main reason could be the steric hindrance
generated after the first coupling. Lindner and colleagues [59], and
recently Engtrakul and Sita [60] noted that the solubility of the resulting compounds was of major importance for the bis-coupling success.
The presence of methoxy and tri-isopropylsilyl groups in the alkyne
moiety allowed the formation of -extended molecules (73) in good
yields. Moderate yields were reported by Ma and colleagues by using
tert-butylsulfanyl groups in the substrates for the synthesis of (74), a
precursor for symmetrical molecular wires [61]. A low yield of bisproduct (75) was obtained by Köcher and colleagues during the
preparation of 4-ferrocenyl-NCN pincer complexes [62], whereas no
expected product was isolated by Gonzalez-Cabello and colleagues
[63]. In this last case the obtained mono-coupling product (76) was
reused in a second Sonogashira reaction but again the bisphthalocyanine ferrocene derivative was not formed (Fig. (14)).
The alkyne functionality was used respectively by Robinson’s
and Woods’ groups as a ligand for cobalt complexes. In the first case,
it was shown that polyferrocenes in (77) can serve as a communicator
linkage between Co2(CO)4dppm units [64]. In the second application,
new ferrocenophane derivatives (78) and (79) bearing two
Co2(CO)8(alkyne) complexes were isolated and studied by electrochemistry [65]. Jaouen’s group showed that the alkyne group can
serve as a linker between chiral ferrocene and oestradiol through the
synthesis of (80) [66] and that the estrogen receptor was capable to
recognize preferentially one diastereoisomer [67]. During this work,
the authors noted that the Sonogashira coupling was more efficient
with iodoferrocene compounds, whereas the Stille coupling was more
310 Mini-Reviews in Organic Chemistry, 2008, Vol. 5, No. 4
V. Mamane
Fe
R1
R2
(81)
ZnCl
Fe
Me2N
2-bromo-indene
Pd cat
R2
R2 = H
40%
R2 = 2-indene 47%
R2 = H or ZnCl
Fe
74%
R2 R2 = H
2 = 2-indene 26%
R
(82)
R = CONEt2
R
R
CH2=CHSnBu3
Fe
69%
R = OCOCN
O 85%
R = OCOCN
82%
Fe
Pd cat
I
(83)
Fig. (16).
CONR2
Fe
Fe
O
R1
(86) 75-94%
N
OMe
Fe
R2
Fe
(87)
R2
O
N
O
O
Fe
O
R1
OMe
N
R
(85)
R = H 57-72%
R = I 11-40%
R
(84)
R=H
71-88%
R = CONR2 70-92%
14-35%
R=I
3.2. Ferrocene-Alkene Bond
R2
O
COCONR2
R1
O
R1
O
N
26-89%
(88)
O
R2
R = Et, n-Bu, -(CH2)5-, -(CH2)2-O-(CH2)2
Two recent examples described the formation of a ferrocenealkene bond on the basis of cross-coupling reaction. A Negishi coupling was used by Anderson and colleagues to introduce one or two
indenyl ligands on the ferrocene to give (81) and (82) [69]. 1Substituted, 1’-vinylferrocenes (83) were prepared in good yields by
Szarka and colleagues by a Stille coupling in presence of vinyltributyltin [70] (Fig. (16)).
OMe
3.3. Ferrocene-CO Bond: Aminocarbonylation
OMe
The aminocarbonylation reaction of iodoferrocene compounds
catalyzed by palladium was intensively used by Skoda-Földes’ group
for the synthesis of amides (84) and -ketoamides (85) [70-72]. The
reaction was described to proceed with both 1-iodoferrocene and
1,1’-diiodoferrocene with moderate to good yields. A nice entry to
ferrocenyl amino acid derivatives (86)-(88) was also described by
using protected amino-acids as the amine partners in the reaction [73,
74] (Fig. (17)).
27-47%
Amino acids : Gly-OMe, L-Ala-OMe, L-Phe-OMe, L-Met-OMe, L-Pro-OMe
Fig. (17).
4. FERROCENE-HETEROATOM BOND FORMATION
practical for other iodocyclopentadienyl complexes (Mn, Re). The
explanation for these interesting observations was reported recently
by Amatore and colleagues [68] (Fig. (15)).
Only a few examples described the direct formation of a ferrocene-heteroatom bond. Copper in catalytic or stoechiometric
amounts is generally preferred to effect these transformations. For the
O
NH2
Hydrazine
Fe
99%
N
R=H
Cu-Phthalimide
82%
Fe
R=I
NaN3
I
Fe
R
N3
N3
59%
O
NH2
H2, Pd/C
Fe
Fe
77%
NH2
R2
(90)
(89)
N
N
Fe
NPh2
X Y
Fe
Fig. (18).
31-84%
(92) 43%
N
N
Fe
X
Fe
R1
N
X, Y = CH, N
(91)
X
N
(93) 50%
N
(94)
X = CH, N
R1, R2 = H, Me, NO2
35-95%
Y
Fe
X, Y = CH, N
(95) 28-96%
Metal-Catalyzed Cross-Coupling Reactions
Mini-Reviews in Organic Chemistry, 2008, Vol. 5, No. 4
preparation of 1,1’-diaminoferrocene (89) and 1-aminoferrocene (90),
improved procedures were reported. Shafir and colleagues described
the synthesis of (89) in two steps from the readily available 1,1’dibromoferrocene [75]. Heinze and Schlenker obtained (90) in good
yield and purity by reacting iodoferrocene with a pre-formed Cuphtalimide complex following by deprotection [76]. Recently, Bolm’s
group described the direct synthesis of N-substituted ferrocenes (91)(93) using stoechiometric amount of CuI in DMSO [77]. A catalytic
protocol for the Ulmann-type coupling was then reported by Nagarkar’s group for the efficient preparation of a range of N-substituted
ferrocenes (94) and (95) [78] (Fig. (18)).
Plenio’s group reported the copper-catalyzed synthesis of ferrocenyl aryl ethers (96)-(98) from iodo-and bromo-ferrocenes in
moderate to good yields [79]. 2,2,6,6-Tetramethylheptane-3,5-dione
(TMHD) was found to be an efficient ligand for copper when this
reaction was carried out in N-methylpyrrolidinone (NMP) solvent
using Cs2CO3 or K3PO4 bases. During their study on the palladiumcatalyzed asymmetric phosphination of iodoarenes, Blank and colleagues reported one example using iodoferrocene [80]. Product (99)
was obtained in quantitative yield but in low ee (Fig. (19)).
[8]
[9]
[10]
[11]
[12]
[13]
[14]
[15]
[16]
[17]
[18]
[19]
[20]
[21]
[22]
[23]
[24]
[25]
R
R
O
O
R'
Fe
Fe
(96) R = H, Me, t-Bu, Cl
24-90%
[26]
[27]
[28]
[29]
[30]
O
[31]
[32]
(97) R, R' = H, Me, t-Bu
[33]
[34]
30-65%
[35]
i-Pr
[36]
P
O
Fe
Me
Fe
[37]
Fe
i-Pr
(98) 22%
i-Pr
(99) 100% yield, 8% ee
Fig. (19).
[38]
[39]
[40]
[41]
5. CONCLUSION
Metal-catalyzed cross-coupling reactions have allowed the formation of new compounds which are not accessible or obtained with low
yields by other methods. These reactions thus widened the utilization
of ferrocenyl compounds in material science and asymmetric catalysis. Direct introduction of heteroatoms on the ferrocene core is still
limited and one could suppose that new methods involving the formation of ferrocene-heteroatom bonds will appear in the near future.
[42]
[43]
[44]
[45]
[46]
[47]
ACKNOWLEDGMENTS
I gratefully acknowledge the CNRS and the Nancy Université for
financial support of my own research in this area.
[48]
[49]
[50]
REFERENCES
[1]
[2]
[3]
[4]
[5]
[6]
[7]
Togni, A.; Hayashi, T. Ferrocenes, VCH-Wiley: Weinheim, Germany, 1995.
Atkinson, R. C. J.; Gibson, V. C.; Long, N. J. Chem. Soc. Rev., 2004, 33,
313.
De Meijere, A., Diederich, F. Metal Catalyzed Cross-Coupling Reactions,
VCH-Wiley: Weinheim, Germany, 1998.
Kasak, P.; Miklas, R.; Putala, M. J. Organomet. Chem., 2001, 637-639, 318326.
Handbook of Organopalladium Chemistry for Organic Synthesis; Negishi,
E.; Ed; Wiley-Interscience: New-York, 2002; vol. 1, Part III.
Miyaura, N.; Suzuki, A. Chem. Rev., 1995, 95, 2457-2483.
Espinet, P.; Echavarren, A. M. Angew. Chem. Int. Ed., 2004, 43, 4704-4734.
[51]
[52]
[53]
[54]
[55]
[56]
[57]
311
Guillaneux, D.; Kagan, H. B. J. Org. Chem., 1995, 60, 2502-2505.
Ferber, B.; Kagan, H. B. Adv. Synt. Catal., 2007, 349, 493-507.
Helberg, F. L.; Rosenberg, H. Tetrahedron Lett., 1969, 10, 4011-4012.
Lee, M.-T.; Foxman, B. M.; Rosenblum, M. Organometallics, 1985, 4, 539547.
Hudson, R. D. A.; Foxman, B. M.; Rosenblum, M. Organometallics, 2000,
19, 469-474.
Malessa, M.; Heck, J.; Kopf, J.; Garcia, M. H. Eur. J. Inorg. Chem., 2006,
857-867.
Barlow, S.; O’Hare, D. Chem. Rev., 1997, 97, 637-669.
Ogawa, S.; Muraoka, H.; Sato, R. Tetrahedron Lett., 2006, 47, 2479-2483.
Yu, Y.; Bond, A. D.; Leonard, P. W.; Vollhardt, K. P. C.; Whitener, G. D.
Angew. Chem. Int. Ed., 2006, 45, 1794-1799.
Yu, Y.; Bond, A. D.; Leonard, P. W.; Lorenz, U. J.; Timofeeva, T. V.; Vollhardt, K. P. C.; Whitener, G. D.; Yakovenko, A. A. Chem. Commun., 2006,
2572-2574.
Mamane, V.; Gref, A.; Lefloch, F.; Riant, O. J. Organomet. Chem., 2001,
637-639, 84-88.
Mamane, V.; Gref, A.; Riant, O. New J. Chem., 2004, 28, 585-594.
Mamane, V.; Ledoux-Rak, I.; Deveau, S.; Zyss, J.; Riant, O. Synthesis, 2003,
455-467.
Enders, M.; Kohl, G.; Pritzkow, H. J. Organomet. Chem., 2001, 622, 66-73.
Horikoshi, R.; Nambu, C.; Mochida, T. Inorg. Chem., 2003, 42, 6868-6875.
Mochida, T.; Okazawa, K.; Horikoshi, R. Dalton Trans., 2006, 693-704.
Mochida, T.; Shimizu, H.; Suzuki, S.; Akasaka, T. J. Organomet. Chem.,
2006, 691, 4882-4889.
Quinodoz, B.; Labat, G.; Stoeckli-Evans, H.; von Zelewsky, A. Inorg.
Chem., 2004, 43, 7994-8004.
Mamane, V.; Fort, Y. J. Org. Chem., 2005, 70, 8220-8223.
Pedersen, H. L.; Johannsen, M. J. Org. Chem., 2002, 67, 7982-7994.
Lotz, M.; Kramer, G.; Knochel, P. Chem. Commun., 2002, 2546-2547.
Kloetzing, R. J.; Knochel, P. Tetrahedron Asymmetry, 2006, 17, 116-123.
Cotton, H. K.; Huerta, F. F.; Bäckvall, J.-E. Eur. J. Org. Chem., 2003, 27562763.
Knapp, R.; Rehahn, M. J. Organomet. Chem., 1993, 452, 235-240.
Imrie, C.; Loubster, C.; Engelbrecht, P.; McCleland, C. W. J. Chem. Soc.
Perkin Trans. 1, 1999, 2513-2523.
Mamane, V.; Riant, O. Tetrahedron, 2001, 57, 2555-2561.
Butler, I. R.; Caballero, A. G.; Kelly, G. A. Inorg. Chem. Commun., 2003, 6,
639-642.
Sailer, M.; Rominger, F.; Müller, T. J. J. J. Organomet. Chem., 2006, 691,
299-308.
Hua, D. H.; McGill, J. W.; Lou, K.; Ueki, A.; Helfrich, B.; Desper, J.; Zanello, P.; Cinquantini, A.; Corsini, M.; Fontani, M. Inorg. Chim. Acta, 2003,
350, 259-265.
Köcher, S.; Lutz, M.; Spek, A. L.; Prasad, R.; van Klink, G. P. M.; van
Koten, G.; Lang, H. Inorg. Chim. Acta, 2006, 359, 4454-4462.
Cammidge, A. N.; Scaife, P. J.; Berber, G.; Hughes, D. L. Org. Lett., 2005,
7, 3413-3416.
Braga, D.; Polito, M.; Bracaccini, M.; D’Addario, D.; Tagliavini, E.; Sturba,
L.; Grepioni, F. Organometallics, 2003, 22, 2142-2150.
Braga, D.; D’Addario, D.; Polito, M.; Grepioni, F. Organometallics, 2004,
23, 2810-2812.
Pena-Cabrera, E.; Aguilar-Aguilar, A.; Gonzalez-Dominguez, M.; Lager, E.;
Zamudio-Vazquez, R.; Godoy-Vargas, J.; Villanueva-Garcia, F. Org. Lett.,
2007, 9, 3985-3988.
Laufer, R. S.; Veith, U.; Taylor, N. J.; Snieckus, V. Org. Lett., 2000, 2, 629631.
Jensen, J. F.; Sotofte, I.; Sorensen, H. O.; Johannsen, M. J. Org. Chem.,
2003, 68, 1258-1265.
Anderson, C. E.; Donde, Y.; Douglas, C. J.; Overman, L. E. J. Org. Chem.,
2005, 70, 648-657.
Stead, R.; Xiao, J. Lett. Org. Chem., 2004, 1, 148-150.
Wang, Y.; Weissensteiner, W.; Spindler, F.; Arion, V. B.; Mereiter, K.
Organometallics, 2007, 26, 3530-3540.
Liu, C.-M.; Chen, B.-H.; Liu, W.-Y.; Wu, X.-L.; Ma, Y.-X. J. Organomet.
Chem., 2000, 598, 348-352.
Liu, C.-M.; Guo, Y.-L.; Wu, X.-L.; Liang, Y.-M.; Ma, Y.-X. J. Organomet.
Chem., 2000, 612, 172-175.
Liu, C.-M.; Liang, Y.-M.; Wu, X.-L.; Liu, W.-M.; Ma, Y. X. J. Organomet.
Chem., 2001, 637-639, 723-726.
Song, H. S.; Li, X.; Long, Y.; Schatte, G.; Kraatz, H.-B. Dalton Trans., 2006,
4696-4701.
Weber, I.; Heinemann, F. W.; Bakatselos, P.; Zenneck, U. Helv. Chim. Acta,
2007, 90, 834-845.
Nguyen, H. V.; Motevalli, M.; Richards, C. J. Synlett, 2007, 725-728.
Chen, Y. J.; Kao, C.-H.; Lin, S. J.; Tai, C.-C.; Kwan, K. S. Inorg. Chem.,
2000, 39, 189-194.
Tsvetkov, A. V.; Latyshev, G. V.; Lukashev, N. V.; Beletskaya, I. P. Tetrahedron Lett., 2000, 41, 3987-3990.
Bringmann, G.; Hinrichs, J.; Peters, K.; Peters, E.-M. J. Org. Chem., 2001,
66, 629-632.
Korn, T. J.; Schade, M. A.; Cheemala, M. N.; Wirth, S.; Guevara, S. A.;
Cahiez, G.; Knochel, P. Synthesis, 2006, 3547-3574.
Chinchilla, R.; Najera, C. Chem. Rev., 2007, 107, 874-922.
312 Mini-Reviews in Organic Chemistry, 2008, Vol. 5, No. 4
[58]
[59]
[60]
[61]
[62]
[63]
[64]
[65]
[66]
[67]
[68]
[69]
V. Mamane
Plenio, H.; Hermann, J.; Sehring, A. Chem. Eur. J., 2000, 6, 1820-1829.
Lindner, E.; Zong, R.; Eichele, K.; Ströbele, M. J. Organomet. Chem., 2002,
660, 78-84.
Engtrakul, C.; Sita, L. R. Organometallics, 2008, 27, 927-937.
Ma, J.; Vollmann, M.; Menzel, H.; Pohle, S.; Butenschön, H. J. Inorg. Organomet. Polym., 2008, 18, 41-50.
Köcher, S.; Walfort, B.; van Klink, G. P. M.; van Koten, G.; Lang, H. J.
Organomet. Chem., 2006, 691, 3955-3961.
Gonzalez-Cabello, A.; Vasquez, P.; Torres, T. J. Organomet. Chem., 2001,
637-639, 751-756.
Hore, L.-A.; McAdam, J.; Kerr, J. L.; Duffy, N. W.; Robinson, B. H.; Simpson, J. Organometallics, 2000, 19, 5039-5048.
Woods, A. D.; Alcalde, G.; Golovko, V. B.; Halliwell, C. M.; Mays, M. J.;
Rawson, J. M. Organometallics, 2005, 24, 628-637.
Ferber, B.; Top, S.; Welter, R.; Jaouen, G. Chem. Eur. J., 2006, 12, 20812086.
Ferber, B.; Top, S.; Vessières, A.; Welter, R.; Jaouen, G. Organometallics,
2006, 25, 5730-5739.
Amatore, C.; Godin, B.; Jutand, A.; Ferber, B.; Top, S.; Jaouen, G. Organometallics, 2007, 26, 3887-3890.
Anderson, J. C.; White, C.; Stenson, K. P. Synlett, 2002, 1511-1513.
Received: March 25, 2008
[70]
[71]
[72]
[73]
[74]
[75]
[76]
[77]
[78]
[79]
[80]
Revised: May 12, 2008
Szarka, Z.; Kuik, A.; Skoda-Földes, R.; Kollar, L. J. Organomet. Chem.,
2004, 689, 2770-2775.
Szarka, Z.; Skoda-Földes, R.; Kollar, L. Tetrahedron Lett., 2001, 42, 739741.
Szarka, Z.; Skoda-Földes, R.; Kuik, A.; Berente, Z.; Kollar, L. Synthesis,
2003, 545-550
Kuik, A.; Skoda-Földes, R.; Balogh, J. Kollar, L. J. Organomet. Chem.,
2005, 690, 3237-3242.
Kuik, A.; Skoda-Földes, R.; Janosi, L. Kollar, L. Synthesis, 2007, 1456-1458.
Shafir, A.; Power, M. P.; Whitener, G. D.; Arnold, J. Organometallics, 2000,
19, 3978-3982.
Heinze, K.; Schlenker, M. Eur. J. Inorg. Chem., 2004, 2974-2988.
Özçubukçu, S.; Schmitt, E.; Leifert, A.; Bolm, C. Synthesis, 2007, 389-392.
Purecha, V. H.; Nandurkar, N. S.; Bhanage, B. M.; Nagarkar, J. M. Tetrahedron Lett., 2008, 49, 1384-1387.
an der Heiden, M. R.; Frey, G. D.; Plenio, H. Organometallics, 2004, 23,
3548-3551.
Blank, N. F.; Moncarz, J. R.; Brunker, T. J.; Scriban, C.; Anderson, B. J.;
Amir, O.; Glueck, D. S.; Zakharov, L. N.; Golen, J. A.; Incarvito, C. D.;
Rheingold, A. L. J. Am. Chem. Soc., 2007, 129, 6847-6858.
Accepted: May 12, 2008