Bis(ferrocenyl)mercury as a source of ferrocenyl moiety in Pd-catalyzed reactions of carbon-carbon bond formation

Article abstract of DOI:10.1016/S0022-328X(01)00979-2

The application of bis(ferrocenyl)mercury as a source of ferrocenyl group in Pd-catalyzed reactions with aryl halides, acid chlorides and electrophilic alkynes has been demonstrated. The formation of dimethyl-(Z)-2,3-di(ferrocenyl)-2-butenedioate in Pd-catalyzed addition of bis(ferrocenyl)mercury to dimethylacetylenedicarboxylate has been confirmed by X-ray analysis.

Full text of DOI:10.1016/S0022-328X(01)00979-2

Journal of Organometallic Chemistry 637–639 (2001) 653–663
www.elsevier.com/locate/jorganchem
Bis(ferrocenyl)mercury as a source of ferrocenyl moiety in
Pd-catalyzed reactions of carbon–carbon bond formation
Irina P. Beletskaya *, Alexei V. Tsvetkov, Gennadij V. Latyshev, Victor A. Tafeenko,
Nikolai V. Lukashev
Department of Chemistry, Moscow State Lomonoso6 Uni6ersity, Leninskie Gory, GSP-3, Moscow 119899, Russia
Received 19 April 2001; received in revised form 8 May 2001; accepted 9 May 2001
Dedicated to Professor J.F. Normant on the occasion of his 65th birthday
Abstract
The application of bis(ferrocenyl)mercury as a source of ferrocenyl group in Pd-catalyzed reactions with aryl halides, acid
chlorides and electrophilic alkynes has been demonstrated. The formation of dimethyl-(Z)-2,3-di(ferrocenyl)-2-butenedioate in
Pd-catalyzed addition of bis(ferrocenyl)mercury to dimethylacetylenedicarboxylate has been confirmed by X-ray analysis. © 2001
Elsevier Science B.V. All rights reserved.
Keywords: Bis(ferrocenyl)mercury; Ferrocenes; Cross-coupling reactions
pounds commonly used in cross-coupling chemistry,
including higher selectivity of reactions, tolerance to a
wide range of important functional groups, as well as
easy availability by a direct mercuration of ferrocene.
In the preliminary communication we have shown that
ferrocenylmercuric compounds are best suited for selec-
tive substitution of one of the halogen atoms in dihalo-
substitued arenes [12]. Here we report the results of our
further investigation on the application of bis(ferro-
cenyl)mercury in the cross-coupling reaction with aryl,
hetaryl, acid halides and in the addition to alkynes.
1. Introduction
The last decade saw a surge of interest in the synthe-
sis of aryl-, alkenyl-, and alkynylsubstituted ferrocenes
owing to their potential applications as NLO chro-
mophores [1], LC materials [2], in electrochemistry [3],
polymer chemistry [4], material chemistry [5,6], etc.
These classes of compounds have been proven to be
most readily accessed by cross-coupling reactions, e.g.
of iodoferrocene with arylboronic acids [7], and organ-
otin compounds [8], or alternatively of aryl halides with
tin [9], and zinc [6,10] derivatives of ferrocene, as well
as ferrocenylboronic acids [11]. These reactions allow to
attach one or several ferrocene residues to the aromatic
ring, and to prepare oligo- and polymeric products, if
bis(tin) or bis(zinc) derivatives of ferrocene are em-
ployed [6,10a,b].
2. Results and discussion
2.1. Reaction of bis( ferrocenyl)mercury with aryl
halides
We have investigated the application of ferro-
cenylmercuric derivatives in cross-coupling reactions
leading to ferrocene-containing conjugated molecules.
The derivatives of mercury have a number of notable
advantages over other sorts of organometallic com-
We have found that cross-coupling of bis(ferro-
cenyl)mercury with aryl iodides can be accomplished in
the presence of 4 mol% of Pd catalyst and four equiva-
lents of iodide salt, such as KI, Bu4N+I− or NaI. As
aryl iodides with electron-withdrawing substituents re-
acted more readily than those with electron-donating
substituents, we have chosen the least reactive substrate
* Corresponding author. Tel./fax: +7-95-939-3618.
E-mail address: beletsk@postman.ru (I.P. Beletskaya).
0022-328X/01/$ - see front matter © 2001 Elsevier Science B.V. All rights reserved.
PII: S0022-328X(01)00979-2

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I.P. Beletskaya et al. / Journal of Organometallic Chemistry 637–639 (2001) 653–663
Scheme 1.
Scheme 2.
4-iodoanisole (67% yield in the initial run in the pres-
ence of PdCl2(PPh3)2 catalyst) in the search for an
optimal catalyst (Scheme 1).
We have found that in the presence of Pd(PPh3)4
bis(ferrocenyl)mercury gives from high to near quanti-
tative yields of the cross-coupling products with a wide
range of aryl iodides. High yields were obtained both
with Pd(PPh3)4 and PdCl2(PPh3)2 (entries 3, 4 and 17)
with aryl iodides bearing electron-withdrawing
substituents.
Ortho-substituted aryl iodides are considerably less
reactive giving lower yields of target products in longer
reaction times (with the exception of 2,4-dini-
troiodobenzene, which readily reacts with bis(ferro-
cenyl)mercury even without Pd catalyst).
In most cases the reactions were complicated by a
competitive formation of bis(ferrocenyl). The yields of
Fc2 were low for reactions with aryl iodides bearing
electron-withdrawing substituents, while in the case of
electron-rich substrates the yield of Fc2 increases to
reach 34% in the cross-coupling with 4-iodophenol,
while the yield of the target arylferrocene (entry 20)
decreases to 24%.
These results can be rationalized by considering two
competing pathways: (i) the oxidative addition of aryl
iodide to Pd(0) and subsequent reaction of arylpalla-
dium intermediate with Fc2Hg giving arylferrocene; (ii)
the possible insertion of Pd(0) into the HgꢀC bond with
subsequent elimination of Hg and Pd(0) giving Fc2 [15].
Electron-withdrawing substituents in aryl iodide facili-
tate the oxidative addition giving preference to the first
The complexes of PdCl2 with dppf, DPEphos, and
acetonitrile were less effective than PdCl2(PPh3)2 and
yielded bis(ferrocenyl) as the main product (yields of
Fc2 were about 70%) with moderate conversions of
starting Fc2Hg. The best result was obtained with
Pd(PPh3)4 to give 80% of the cross-coupling product
with quantitative conversion of Fc2Hg. Iodide ions may
perform multiple functions, from the regeneration of
bis(ferrocenyl)mercury from less reactive FcHgI, to the
nucleophilic catalysis well known in the reactions of
organomercury compounds [13]. Halide ions have re-
cently been reported to enhance the reactivity of ze-
rovalent palladium through the formation of
electron-rich anionic complexes [Pd(0)Hal]− [14]. The
best results were obtained in the presence of NaI in
THF–acetone (3:2, v/v) solvent at reflux. A higher
temperature of the reaction allowed to markedly reduce
the time of reaction. It should be noted that both
ferrocene fragments of Fc2Hg were involved in the
reaction. The use of FcHgCl instead of Fc2Hg under
the same conditions gave lower yield of the cross-cou-
pling product (52 vs. 80%).
The procedure elaborated for 4-iodoanisole was used
to perform the reactions of bis(ferrocenyl)mercury with
other aryl (hetaryl) iodides (Scheme 2). The results are
shown in Table 1.
Scheme 3.

I.P. Beletskaya et al. / Journal of Organometallic Chemistry 637–639 (2001) 653–663
655
Table 1
The yields of cross-coupling products in the reaction of Fc2Hg with aryl halides
Scheme 4.
pathway. Both pathways may involve nucleophilic
Selective substitution of iodine atom occurred in the
catalysis by iodide ions (Scheme 3).
cross-coupling reactions of 4-iodobromobenzene and
4,4%-iodobromobiphenyl (Table 1, entries 5 and 7) with
bis(ferrocenyl)mercury. The products of substitution of
both halide atoms were formed in only 4–9% yields.
Though chlorine atom in 4-chloro-6-iodoquinoline is
The reaction with 1,4-diiodobenzene leads to a di-
substituted product in high yield (92%) (even in the
presence of 50% excess of 1,4-diiodobenzene the disub-
stituted product predominates) (Scheme 4).

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quite reactive in nucleophilic substitution, cross-cou-
pling of this substrate gave exclusively 4-chloro-6-ferro-
cenylquinoline in high yield (entry 19) (Scheme 5).
Under the conditions reported the substitution of
bromine atom can be realized for substrates bearing
electron-withdrawing substituents, such as 4-bromoace-
tophenone (entry 21).
ferrocenyl-4¦-methyl-[1,1%;4%,1¦]terphenyl in 64 and 68%
yields, respectively. We have also shown the principal
possibility of Heck reaction of 4-ferrocenylbromoben-
zene with 4-vinylpyridine to give the respective stilba-
zole dye in moderate yield. Similar structures were
recently proposed for NLO applications [1c], and our
further investigation in this field is now under way.
4-Ferrocenylbromobenzene and 4,4%-ferrocenylbro-
mobiphenyl could be used for further substitution of
bromine atom by cross-coupling or Heck reactions to
give extended systems potentially usable for the synthe-
sis of new NLO of LC materials. Among the methods
applicable for this purpose are (1) cross-coupling of
organometallic derivative (M=B, Sn, Zn) obtained
through lithiation of the above-mentioned ferrocenyl-
halogenarenes with an appropriate aryl or alkenyl
halide; (2) the cross-coupling of bromoarylferrocenes
with an appropriate organometallic compound; (3) the
Heck reaction (Scheme 6). The attempts to use the
cross-coupling of the respective zinc derivative obtained
through the lithiation of 4-ferrocenylbromobenzene
failed, as phenylferrocene was obtained as the only
product formed through reductive debromination. The
expected cross-coupling product was not observed even
in trace amounts. Notable with respect to this also are
low yields of Grignard reagents from 4-bromophenyl-
ferrocene [16]. Nevertheless, 4-ferrocenylbromobenzene
and 4,4%-ferrocenylbromobiphenyl smoothly reacted
with 4-tolylboronic acid to give the expected cross-cou-
pling products 4-ferrocenyl-4%-methylbiphenyl and 4-
2.2. Reaction of bis( ferrocenyl)mercury with acid
chlorides
The procedure elaborated for arylation of bis(ferro-
cenyl)mercury has been applied for palladium-catalyzed
acylation with acid chlorides. This reaction has also
been established to require I− as nucleophilic co-cata-
lyst. Acetone has been used as solvent, as THF is
cleaved by acid chlorides in the presence of iodide ion.
The variation of catalysts has been performed for the
reaction with 4-chlorobenzoyl chloride. In the presence
of phosphine complexes of palladium (Pd(PPh3)4 and
PdCl2(PPh3)2) the reaction at room temperature was
found to be slow, and elevated temperatures were re-
quired to achieve moderate conversions. On the other
hand, phosphine-free palladium complexes, such as
PdCl2(MeCN)2 or Pd(OAc)2 were very efficient to af-
ford quantitative yields after 30 min stirring at room
temperature (Scheme 7). This procedure has been used
to carry out the reactions with other acid chlorides. The
results are listed in Table 2.
Scheme 5.
Scheme 6.

I.P. Beletskaya et al. / Journal of Organometallic Chemistry 637–639 (2001) 653–663
657
Scheme 7.
While the yields obtained with aroyl chlorides were
consistently high, the reaction with cinnamoyl chloride
gave a moderate yield (entry 5). In the latter case
considerable quantity of bis(ferrocenyl) and ferrocene
were found among products of the reaction.
The reaction of bis(ferrocenyl)mercury with 4-bro-
mobenzoyl chloride is not selective, as both reactive
centers are involved in apparently comparable rates. As
was shown above, electron-withdrawing groups activate
the bromine atom in the benzene ring towards substitu-
tion (Scheme 8).
PdCl2(PPh3)2 under the same conditions as described
above the respective adduct is formed in 40% yield. The
results with other diarylmercuric compounds fall out-
side of the scope of this article and will be discussed
elsewhere. On the other hand, the variation of alkyne
was less successful, tolane and perfluorotolane gave Fc2
as main product. Methyl propiolate reacted unselec-
tively to give a complex mixture of products.
As soon as the reaction with Fc2Hg does not require
the presence of oxidant, the catalytic cycle is obviously
driven by Pd(0), with the FcHgPdFc intermediate
formed not by a usual route of transmetallation, but by
oxidative addition of Fc2Hg to Pd(0). Alkyne is likely
to play an auxiliary role of supporting ligand prevent-
ing the formation of palladium black in the absence of
phosphine ligands. A tentative mechanism is given in
Scheme 11.
The insertion of Pd(0) into the CꢀHg bond is a facile
process not requiring phosphine ligands [15]. Moreover,
the latter apparently have a deleterious effect, likely due
to a retardation of a key step of reaction, the addition
of intermediate A to the triple bond [the yield dropped
from 72% for phosphine-free system down to a modest
31–32% obtained in the presence of Pd(PPh3)4 or
PdCl2(PPh3)2]. The elimination of Hg and Pd(0) leads
to the target adduct. Alternatively, the intermediate A
can eliminate Hg and Pd and give Fc2. Apparently, this
2.3. Addition of bis( ferrocenyl)mercury to
dimethylacetylenedicarboxilate
The carbopalladation of triple bond is known to be
realized via two alternative ways depending on which
precursor is taken for the generation of organopalla-
dium intermediate—aryl halide (triflate, etc.) [17] or
organometallic compound (possibly generated from a
hydrocarbon in situ) [18]. The vinylpalladium interme-
diate formed by carbopalladation should be trapped to
form stable products in a cascaded process. Among the
numerous cascades initiated by carbopalladation of
triple bond described in the literature [19], alkoxycar-
bonylation (Scheme 1, route ‘a’) or hydride transfer
(route ‘b’) are the best studied termination reactions for
Pd(0) driven processes. In more rare Pd(II) driven
processes vinylpalladium intermediate can be pro-
tolyzed by acid (route ‘c’) or trapped by nucleophilic
organometallics (e.g. organotin compound). In the lat-
ter case the regeneration of Pd(II) requires the presence
of an oxidant (route ‘d’) [18d] (Scheme 9).
Table 2
Yields of acylferrocenes in cross-coupling of Fc2Hg with acid chlo-
rides (4 mol% Pd(MeCN)2Cl2)
We have shown that bis(ferrocenyl)mercury reacts in
the presence of palladium catalyst and NaI with
dimethyl acetylenedicarboxylate to give the product of
syn-addition of two ferrocenyl residues to the triple
bond. The formation of bis(ferrocenyl) as side product
was also observed (Scheme 10).
The reaction can be catalyzed by either Pd(II) or
Pd(0) complexes. The best yields were obtained for
ligandless Pd catalysts (Table 3). For example, the
reaction in the presence of PdCl2 or Pd(OAc)2 after 30
min refluxing in THF–acetone mixture gave 69–72%
dimethyl (Z)-2,3-di( ferrocenyl)-2-butenedioate along
with 20% Fc2. The formation of the E-adduct has not
been observed.
Other diarylmercuric compounds can be used as well,
e.g. in the reaction of dianisylmercury catalyzed by

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I.P. Beletskaya et al. / Journal of Organometallic Chemistry 637–639 (2001) 653–663
Scheme 8.
Scheme 9.
Scheme 10.
side process prevails for alkynes with less electrophilic
triple bond in comparison with dimethyl
acetylenedicarboxylate.
to be accounted for by a considerable conformational
mobility of the cycles in crystal. This conclusion is
supported by the ORTEP plot in Fig. 1 which shows
markedly larger thermal ellipsoids of free Cp rings, as
compared to Cp rings bonded to the olefinic fragment.
It is worth noting that the tilt angle of the cycle
(C35ꢀC39) plane relative to the cycle (C30ꢀC34) plane
is equal to 8.3(5)°, while the angle between cycle
(C55ꢀC59) and cycle (C50ꢀC54) is equal to 10.5°, which
The structure of dimethyl (Z)-2,3-di(ferrocenyl)-2-
butenedioate was established by X-ray spectroscopy.
The unit cell contains two independent molecules of
dimethyl (Z)-2,3-di(ferrocenyl)-2-butenedioate (Table
4). The ORTEP drawing of these molecules is presented
in Fig. 1 together with the atomic labeling scheme.
Let us denote the molecules M(2,3) and M(4,5) in
accordance with the numbering of iron atoms. Bond
distances FeꢀC in Cp rings for molecules M(2,3) and
M(4,5) are equal within experimental error to 2.037(5)
Table 3
The dependence of yield of dimethyl (Z)-2,3-di(ferrocenyl)-2-butene-
dioate on catalyst
,
A. Average lengths of bonds Fe(3)ꢀ(C35–C39) in
Catalyst
Time (h)
Yield a (%)
molecule M(2,3) and Fe(5)ꢀ(C55–C59) in molecule
,
M(4,5) are slightly smaller to be equal to 2.029(5) A for
Fe(3)ꢀ(C35–C39) and 2.022(5) A for Fe(5)ꢀ(C55–C59).
For the same cycles an average bond length of the
carbon–carbon bond also have a minimal value of
1.392(6) A in comparison with the carbon–carbon
bond lengths in other Cp cycles. This deviation is likely
Pd(PPh3)4
PdCl2(PPh3)2
PdCl2(MeCN)2
PdCl2
1.5
1.5
1.5
0.5
0.5
31
32
38
72
69
,
Pd(OAc)2
,
a Isolated yield.

I.P. Beletskaya et al. / Journal of Organometallic Chemistry 637–639 (2001) 653–663
659
Scheme 11.
is also larger than the tilt angle of cycle (C20ꢀC24)
relative to cycle (C25ꢀC29) being equal to 7.1(5)°, and
the angle between cycle (C40ꢀC44) and cycle (C45ꢀ-
C47) being equal to 3.7(5)°.
vacuum. The product was purified by column chro-
matography using
elution.
a benzene–hexane mixture for
The molecules are sterically crowded, which leads to
considerable deformations of bond angles in the olefinic
fragment for both molecules. Thus, in M(2,3) the angles
are: C(8)ꢀC(3)ꢀC(2)—120.6(4), C(3)ꢀC(2)ꢀC(6)—
120.4(4), C(8)ꢀC(3)ꢀC(34)—114.5(4), C(6)ꢀC(2)ꢀC(28)
—114.3 (4), C(2)ꢀC(3)ꢀC(34)—124.9(5), C(3)ꢀC(2)ꢀ
C(28)—125.2(5), while the respective angles in M(4,5)
are equal to 121.2(4), 120.6(4), 113.6(4), 115.3(4),
125.2(4), 125.0(4)°.
3.1.2. 4-Methoxyphenylferrocene
Orange solid (80%, m.p. 106–107 °C, lit. 113 °C
1
[7a]). H-NMR (CDCl3): 7.38 (m, 2H), 6.83 (m, 2H),
4.56 (m, 2H), 4.25 (m, 2H), 4.02 (s, 5H), 3.80 (s, 3H).
3.1.3. 4-Fluorophenylferrocene
Orange solid (92%, m.p. 106 °C, lit. 104 °C [7a]).
1H-NMR (CDCl3): 7.42 (m, 2H), 6.97 (m, 2H), 4.57 (m,
2H), 4.28 (m, 2H), 4.02 (s, 5H).
Selected dihedral angles characteristic for defining the
molecular structure are given in Table 5. For both
molecules iron atoms Fe(2), Fe(3) and Fe(4), Fe(5)
deviate to opposite directions from the least-squares
plane of the olefinic fragment C(6)ꢀC(2)ꢀC(3)ꢀC(8). In
M(2,3) the deviation of iron atoms from the least-
3.1.4. 4-Nitrophenylferrocene
Dark-red solid (96%, m.p. 171 °C, lit. 169–170 °C
1
[20]). H-NMR (CDCl3): 8.12 (m, 2H), 7.54 (m, 2H),
4.73 (m, 2H), 4.46 (m, 2H), 4.04 (s, 5H).
Table 4
,
squares plane C(6)ꢀC(2)ꢀC(3)ꢀC(8) are (+1.704 A) for
Crystal data and structure refinement for dimethyl (Z)-2,3-di(ferro-
cenyl)-2-butenedioate
,
Fe(2), and (−1.425 A) for Fe(3), while the respective
,
deviations in M(4,5) are (+1.430 A) for Fe(4), and
(−1.440 A) for Fe(5). The oxygen atoms of carbonyl
,
Empirical formula
Formula weight
Color
C26H24Fe2O4
511.7
Red
groups are also located at different sides of the olefinic
fragment plane both with respect to each other and
with respect to the closest iron atom. The iron–oxygen
bond distances (of carbonyl and methoxy groups) are
Temperature (K)
293(2)
,
Wavelength (A)
0.71073
Triclinic
P1
Crystal system
Space group
,
within
Fe(2)ꢀO(2)—4.040(5) A, Fe(3)ꢀO(3)—4.145(5) A,
a narrow range: Fe(2)ꢀO(1)—4.054(5) A,
(
,
,
Unit cell dimensions
,
a (A)
9.114(2)
,
,
Fe(3)ꢀO(4)—3.793(5) A; Fe(4)ꢀO(5)—3.823(5) A,
,
b (A)
11.370(3)
23.386(3)
89.58(2)
91.19(2)
111.87(3)
4
,
,
Fe(4)ꢀO(6)—4.184(5) A, Fe(5)ꢀO(7)—4.060(4) A,
,
c (A)
,
Fe(5)ꢀO(8)—3.954(5) A.
h (°)
i (°)
k (°)
Z
3. Experimental
Crystal size (mm)
Theta range for data collection
(°)
0.05×0.07×0.08
0.87–25.98
3.1. The reactions of bis( ferrocenyl)mercury with aryl
and hetaryl halides
Index ranges
−115h511,−145k514,
05l528
Reflections collected/unique
Reflections observed [I\2|(I)]
Number of parameters refined
Completeness to q=25.98 (%)
Refinement method
9037/8808 [Rint=0.0222]
6111
3.1.1. General procedure
In a flask equipped with reflux condenser and gas
inlet 70 mg Fc2Hg (0.12 mmol), ArI (0.28 mmol), 74 mg
NaI (0.48 mmol), 3 ml absolute THF, and 2 ml abso-
lute Me2CO were placed under Ar atmosphere. To the
reaction mixture heated to boiling a catalyst (4.8 mmol,
4 mol%) was added. After the mixture was stirred at
reflux for the time given in Table 1 (TLC control), it
was filtered through a pad of silica and evaporated in
583
100.0
Full-matrix least-squares on F2
0.976
Goodness-of-fit on F2
Final R indices [I\2|(I)]
R indices (all data)
R=0.0515, a Rw=0.1187 b
R=0.0858, a Rw=0.1370 b
a R=ꢀꢁFoꢂ−ꢂFcꢁ/ꢀꢂFoꢂ.
b Rw={ꢀ[W(Fo2−Fc2)2]/ꢀ[W(F2o)2]}1/2
.

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I.P. Beletskaya et al. / Journal of Organometallic Chemistry 637–639 (2001) 653–663
Fig. 1. The ORTEP drawing of two independent molecules of the unit cell of dimethyl (Z)-2,3-di(ferrocenyl)-2-butenedioate.
3.1.5. 4-Cyanophenylferrocene
3.1.11. 4-Methylphenylferrocene
Orange–red solid (97%, m.p. 141–142 °C, lit. 145–
146 °C [20]). H-NMR (CDCl3): 7.52 (m, 4H), 4.68 (m,
Orange solid (90%, m.p. 136–138 °C, lit. 140–
142 °C [20]). H-NMR (CDCl3): 7.36 (m, 2H), 7.08 (m,
1
1
2H), 4.41 (m, 2H), 4.03 (s, 5H).
2H), 4.59 (m, 2H), 4.26 (m, 2H), 4.01 (s, 5H), 2.31 (s,
3H).
3.1.6. 4-Bromphenylferrocene
3.1.12. 4-Tetradecyloxyphenylferrocene
Orange solid (84%, m.p. 93 °C). H-NMR (CDCl3):
7.37 (m, 2H), 6.82 (m, 2H), 4.54 (m, 2H), 4.24 (m, 2H),
4.01 (s, 5H), 3.94 (t, 2H), 1.78 (m, 2H), 1.43 (m, 2H),
1.25 (m, 20H), 0.87 (t, 3H). Anal. Found: C, 75.99; H,
9.00. Calc. for C30H42FeO: C, 75.94; H, 8.92%.
Orange–red solid (88%, m.p. 124 °C, lit. 122–
1
1
123 °C [20]). H-NMR (CDCl3): 7.58 (m, 2H), 7.32 (m,
2H), 4.59 (m, 2H), 4.31 (m, 2H), 4.02 (s, 5H).
3.1.7. 4-Cyano-4%-ferrocenylbiphenyl
Orange–red solid (97%, m.p. 190 °C). 1H-NMR
(CDCl3): 7.69 (m, 4H), 7.53 (m, 4H), 4.68 (m, 2H), 4.35
(m, 2H), 4.05 (s, 5H). Anal. Found: C, 76.06; H, 4.40;
N, 3.54. Calc. for C23H17FeN: C, 76.05; H, 4.72; N,
3.86%.
3.1.13. 2-Thienylferrocene
Orange–red solid (90%, m.p. 121–122 °C, lit. 116–
1
118 °C [21]). H-NMR (CDCl3): 77.13 (m, 1H), 6.98
(m, 1H), 6.90 (m, 1H), 4.55 (m, 2H), 4.25 (m, 2H), 4.07
(s, 5H).
3.1.8. 4-Bromo-4%-ferrocenylbiphenyl
Orange–red solid (88%, m.p. 199 °C). 1H-NMR
(CDCl3): 7.53 (m, 4H), 7.46 (m, 4H), 4.66 (m, 2H), 4.33
(m, 2H), 4.05 (s, 5H). Anal. Found: C, 64.93; H, 4.36;
Fe, 13.15. Calc. for C22H17BrFe: C, 65.35; H, 4.11; Fe,
13.39%.
3.1.14. 3-Trifluoromethylphenylferrocene
Orange–red solid (96%, m.p. 96 °C, lit. 97.5–98 °C
1
[20]). H-NMR (CDCl3): 7.64 (m, 2H), 7.39 (m, 2H),
4.66 (m, 2H), 4.35 (m, 2H), 4.03 (s, 5H).
3.1.9. 4-Ferrocenyl-4%-nitrobiphenyl
Red solid (95%, m.p. 224–225 °C). 1H-NMR
(CDCl3): 7.74 (m, 2H), 7.55 (m, 4H), 7.28 (m, 2H), 4.70
(m, 2H), 4.37 (m, 2H), 4.06 (s, 5H). Anal. Found: C,
68.50; H, 4.78; N, 3.14. Calc. for C22H17FeNO2: C,
68.95; H, 4.47; N, 3.66%.
Table 5
Selected dihedral angles (°) for dimethyl (Z)-2,3-di(ferrocenyl)-2-
butenedioate
C(29)ꢀC(28)ꢀC(2)ꢀC(3) 152.4(4) C(4)ꢀC(5)ꢀC(47)ꢀC(46) 139.7(5)
C(3)ꢀC(2)ꢀC(28)ꢀFe(2) 119.8(4) Fe(4)ꢀC(47)ꢀC(5)ꢀC(4) 130.5(4)
C(2)ꢀC(3)ꢀC(34)ꢀC(33) 44.9(6) C(51)ꢀC(50)ꢀC(4)ꢀC(5) 37.4(6)
C(2)ꢀC(3)ꢀC(34)ꢀFe(3) 133.4(4) Fe(5)ꢀC(50)ꢀC(4)ꢀC(5) 126.2(4)
C(6)ꢀC(2)ꢀC(3)ꢀC(8)
C(28)ꢀC(2)ꢀC(3)ꢀC(34)
C(3)ꢀC(2)ꢀC(6)ꢀO(2)
C(2)ꢀC(3)ꢀC(8)ꢀO(4)
3.1.10. 4-Ethoxycarbonylphenylferrocene
5.6(6) C(10)ꢀC(4)ꢀC(5)ꢀC(12)
8.7(7) C(47)ꢀC(5)ꢀC(4)ꢀC(50)
122.3(5) O(5)ꢀC(10)ꢀC(5)ꢀC(4) 129.1(5)
126.4(5) O(8)ꢀC(12)ꢀC(4)ꢀC(5) 120.6(5)
2.9(6)
6.0(4)
Orange–red solid (97%, m.p. 92–93 °C, lit. 88–
1
90 °C [20]). H-NMR (CDCl3): 7.94 (m, 2H), 7.48 (m,
2H), 4.71 (m, 2H), 4.38 (m, 2H), 4.36 (q, 2H), 4.03 (s,
5H), 1.39 (t, 3H).

I.P. Beletskaya et al. / Journal of Organometallic Chemistry 637–639 (2001) 653–663
661
3.1.15. 2-Trifluoromethylphenylferrocene
column chromatography on silica with benzene–hexane
Orange–red solid (60%, m.p. 52 °C, lit. 80–82 °C
[22]). 1H-NMR (CDCl3): 8.03 (m, 1H),7.58 (m, 1H),
7.49 (m, 1H), 7.30 (m, 1H), 4.55 (m, 2H), 4.30 (m, 2H),
4.14 (s, 5H). Anal. Found: C, 61.99; H, 3.85. Calc. for
C17H13F3Fe: C, 61.85; H, 3.97%.
mixture as eluent.
3.2.2. 4-Ferrocenyl-4%-methylbiphenyl
Orange solid (64%, m.p. 181 °C). H-NMR (CDCl3):
7.49 (m, 6H), 7.23 (m, 2H), 4.69 (m, 2H), 4.35 (m, 2H),
4.08 (s, 5H), 2.38 (s, 3H). Anal. Found: C, 78.25; H,
5.97; Fe, 15.72. Calc. for C23H20Fe: C, 78.42; H, 5.72;
Fe, 15.85%.
1
3.1.16. 2,4-Dinitrophenylferrocene
Black solid (96%, m.p. 162 °C, lit. 160 °C [23]).
1H-NMR (CDCl3): 8.32 (m, 1H), 8.27 (m, 1H), 7.91 (m,
1H), 4.58 (m, 2H), 4.52 (m, 2H), 4.12 (s, 5H).
3.2.3. 4-Ferrocenyl-4¦-methyl-[1,1%;4%,1¦]terphenyl
Orange solid (68%, m.p. (dec.) \270 °C). H-NMR
1
(CDCl3): 7.64 (m, 4H), 7.53 (m, 4H), 7.41 (m, 2H), 7.26
(m, 2H), 4.84 (m, 2H), 4.49 (m, 2H), 4.19 (s, 5H), 2.39
(s, 3H). Anal. Found: C, 81.58; H, 5.63; Fe, 12.69.
Calc. for C29H24Fe: C, 81.32; H, 5.65; Fe, 13.04%.
3.1.17. 2-Ethoxycarbonylphenylferrocene
Orange–red solid (85%, m.p. 51–52 °C). H-NMR
(CDCl3): 7.79 (m, 1H), 7.47 (m, 1H), 7.40 (m, 1H), 7.23
(m, 1H), 4.44 (m, 2H), 4.26 (m, 2H), 4.17 (q, 2H), 4.07
(s, 5H), 1.17 (t, 3H). Anal. Found: C, 68.46; H, 5.71.
Calc. for C19H18FeO: C, 68.29; H, 5.43%.
1
3.3. The reaction of bis( ferrocenyl)mercury with acid
chlorides
3.1.18. 3-Pyridylferrocene
3.3.1. General procedure
Orange–red solid (84%, m.p. 57 °C, lit. 57–59 °C
In a flask equipped with reflux condenser and gas
inlet 70 mg Fc2Hg (0.12 mmol), ArCOCl (0.28 mmol),
74 mg NaI (0.48 mmol), and 4 ml dry Me2CO were
placed. Pd(MeCN)2Cl2 (1.3 mg, 4.8 mmol, 4 mol%) was
added to the reaction mixture. After stirring at room
temperature (the course of reaction was followed by
TLC), the mixture was passed through a pad of silica,
and evaporated in vacuum. The product was purified
by column chromatography (silica, benzene as eluent).
1
[24]). H-NMR (CDCl3): 8.74 (m, 1H), 8.42 (m, 1H),
7.72 (m, 1H), 7.21 (m, 1H), 4.66 (m, 2H), 4.37 (m, 2H),
4.05 (s, 5H).
3.1.19. 1,4-Diferrocenylbenzene
1H-NMR (CDCl3): 7.38 (s, 4H), 4.63 (m, 4H), 4.30
(m, 4H), 4.04 (s, 10H) [10b].
3.1.20. 4-Chloro-6-ferrocenylquinoline
Orange–red solid (92%, m.p. 137 °C). 1H-NMR
(CDCl3): 8.69 (d, 1H), 8.18 (d, 1H), 8.03 (d, 1H), 7.91
(dd, 1H), 7.44 (d, 1H), 4.79 (m, 2H), 4.41 (m, 2H), 4.05
(s, 5H). Anal. Found: C, 65.52; H, 4.33; N, 3.84. Calc.
for C19H14ClFeN: C, 65.65; H, 4.06; N, 4.03%.
3.3.2. Benzoylferrocene
Orange–red solid (96%, m.p. 104–105 °C, lit. 108–
1
109 °C [25]). H-NMR (CDCl3): 7.87 (m, 2H), 7.49 (m,
3H), 4.89 (m, 2H), 4.58 (m, 2H), 4.20 (s, 5H).
3.3.3. 4-Chlorobenzoylferrocene
3.1.21. 4-Hydroxyphenylferrocene
Orange–red solid (98%, m.p. 119 °C, lit. 121–
1H-NMR (CDCl3): 7.34 (m, 2H), 6.76 (m, 2H), 4.84
(s, 1H), 4.54 (m, 2H), 4.25 (m, 2H), 4.02 (s, 5H) [20].
1
122 °C [25]). H-NMR (CDCl3): 7.84 (m, 2H), 7.43 (m,
2H), 4.86 (m, 2H), 4.59 (m, 2H), 4.19 (s, 5H).
3.1.22. 4-Ferrocenylacetophenone
3.3.4. 4-Bromobenzoylferrocene
Orange–red solid (m.p. 175–176 °C, lit. 173–174 °C
Orange–red solid (18%, m.p. 121–122 °C, lit. 123–
1
1
[20]). H-NMR (CDCl3): 7.86 (m, 2H), 7.51 (m, 2H),
124 °C [25]). H-NMR (CDCl3): 7.76 (m, 2H), 7.59 (m,
4.72 (m, 2H), 4.40 (m, 2H), 4.04 (s, 5H), 2.58 (s, 3H).
2H), 4.86 (m, 2H), 4.59 (m, 2H), 4.18 (s, 5H).
3.2. Suzuki coupling of bromoarylferrocenes with
4-tolylboronic acid
3.3.5. 4-Ferrocenylbenzoylferrocene
Orange–red solid (81%, m.p. 195 °C). 1H-NMR
(CDCl3): 7.85 (m, 2H), 7.54 (m, 2H), 4.92 (m, 2H), 4.71
(m, 2H), 4.97 (m, 2H), 4.39 (m, 2H), 4.21 (s, 5H), 4.06
(s, 5H). Anal. Found: C, 67.96; H, 5.12. Calc. for
C27H22Fe2O: C, 68.39; H, 4.68%.
3.2.1. General procedure
In a flask equipped with reflux condenser and gas
inlet 0.150 mmol of bromoarylferrocene, 0.165 mmol
4-tolylboronic acid, 0.450 mmol K2CO3 were dissolved
in 3 ml of THF and 1 ml of water under Ar atmo-
sphere. Pd(PPh3)4 (6.0 mmol, 4 mol%) was added and
the solution was stirred at reflux for 24 h. Solvents were
evaporated in vacuum and the residue was purified by
3.3.6. 2-Furoylferrocene
Orange–red solid (98%, m.p. 80 °C, lit. 80 °C [26]).
1H-NMR (CDCl3): 7.64 (m, 1H), 7.32 (m, 1H), 6.57 (m,
1H), 5.14 (m, 2H), 4.61 (m, 2H), 4.19 (s, 5H).

662
I.P. Beletskaya et al. / Journal of Organometallic Chemistry 637–639 (2001) 653–663
3.3.7. (E)-Cinnamoylferrocene
4. Supplementary material
Orange–red solid (38%, m.p. 136 °C, lit. 139–
1
140 °C [27]). H-NMR (CDCl3): 7.78 (d, J=15.8 Hz,
Crystallographic data for the structural analysis have
been deposited with the Cambridge Crystallographic
Data Centre, CCDC no. 158165 for compound
dimethyl (Z)-2,3-di(ferrocenyl)-2-butenedioate. Copies
of this information may be obtained free of charge
from The Director, CCDC, 12 Union Road, Cam-
bridge CB2 1EZ, UK (Fax: +44-1223-336033; e-mail:
deposit@ccdc.cam.ac.uk or www: http://www.ccdc.
cam.ac.uk).
1H), 7.64 (m, 2H), 7.41 (m, 2H), 7.12 (d, J=15.8 Hz,
1H), 4.90 (m, 2H), 4.58 (m, 2H), 4.20 (s, 5H).
3.4. Dimethyl (Z)-2,3-di( ferrocenyl)-2-butenedioate
In a flask equipped with reflux condenser and gas
inlet 70 mg Fc2Hg (0.12 mmol), 34 mg dimethyl
acetylenedicarboxylate (0.24 mmol), 74 mg NaI (0.48
mmol), 2 ml dry THF, and 2 ml dry Me2CO were
placed under Ar atmosphere. After heating to reflux a
catalyst (12 mmol, 10 mol%) was added to the reaction
mixture. The mixture was stirred at reflux (the course of
reaction was followed by TLC), passed through a pad
of silica, and evaporated in vacuum. The product was
purified by column chromatography (silica, benzene as
eluent), (72%, m.p. 173–174 °C). 1H-NMR (CDCl3):
4.21 (m, 4H), 4.17 (m, 4H), 4.03 (s, 10H), 3.87 (s, 6H).
13C-NMR (CDCl3): 167.83, 132.99, 77.41, 70.22, 69.28,
68.82, 51.85. Anal. Found: C, 59.62; H, 5.09; Fe, 22.36.
Calc. for C26H24Fe2O4: C, 60.97; H, 4.72; Fe, 21.81%.
Acknowledgements
We are grateful to Russian Foundation for Basic
Research (grant nos. 00-15-97406 and 01-03-33144) and
foundation ‘Integration of High School and Academy
of Sciences’ (grant AO-115) for financial support.
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