1574
GUSHCHIN et al.
phenyl (III). The latter two compounds are always
isolated in the C-phenylation reactions of ester I and
organic derivatives of antimony and bismuth. They
contain phenyl groups and, therefore, are themselves
able to effect arylation of ester I, involving Pd(II), and
thus to compete with Bi- and Sb-containing phenylat-
ing agents. Danno et al. [12, 13] have studied in detail
such olefin arylation with arenes at 80 110 C.
pared by reactions of Ph3Bi with t-BuO2H and car-
boxylic acids in 90 and 80% yields, respectively [1].
Ph3Sb(OAc)2 and Ph3SbCl2 were prepared by reac-
tions of Ph3Sb with hydrogen peroxide and acids in
85 and 94% yields, respectively [18]. Palladium black
was prepared in 90% yield by reduction of PdCl2 with
formic acid [19]. Li2PdCl4 was prepared in nearly
quantitative yield from PdCl2 and LiCl in water [7].
Na2Pd(OAc)2Cl2 and NaPd(OAc)Cl2 were prepared in
situ from PdCl2 and NaOAc in acetic acid. Pd(OAc)2
was synthesized by oxidation of palladium black with
nitric acid in AcOH for 30 h in 80% yield (after re-
crystallization from AcOH [20]). Pd2(dba)3(CHCl3)
was prepared by reduction of PdCl2 with methanol in
the presence of dibenzylideneacetone [21] in 66%
yield. Ester I was washed with aqueous alkali, dried
with Na2SO4, and distilled. Acetonitrile was allowed
to stand over K2SO3 and twice distilled over phos-
We found that ester II, compound III, as well as
benzene and chlorobenzene have almost no effect on
arylation in the conditions chosen. Thus, upon heating
of benzene with Pd(OAc)2 and ester I (1:1:10) in
MeCN at 50 C for 5 h in air, the yield of ester II is
as low as 0.2%, and 98.8% of benzene remains un-
reacted. Similarly, ester II, chlorobenzene, and com-
pound III were recovered (98, 97, and ca. 100%,
respectively) upon heating with Pd(OAc)2 and ester I.
In the above consideration of the results of phenyla- phoric anhydride [22].
tion of ester I with systems including organic deri-
Reaction of triphenylantimony with palla-
vatives of antimony(III, V), bismuth(III, V), and
palladium(II) we did not dwell on the formation of
compound III. This side reaction involves homo-
coupling of the organometallic substrates in the
presence of palladium(II) complexes [scheme (10)].
dium(II) acetate and ester I in the absence of air.
One neck of an H-shaped ampule was charged with
0.177 g of Ph3Sb and 0.05 g Pd(OAc)2, and the other,
with 4 ml of acetonitrile, 0.45 ml of ester I. The
ampule was degassed, sealed, the reagents were mixed,
and the mixture was heated for 50 h at 50 C. The
ampule was then unsealed, and the liquid was re-
condensed into a liquid nitrogen trap and analyzed.
Acetic acid (0.015 g) was determined by alkaline titra-
tion, and ester II (0.004 g), by GLC. The solid residue
was treated with benzene (2 7 ml). The benzene
extract was centrifuged and analyzed by GLC to find
ester II (0.016 g) and compound III (0.002 g).
Pd(0)n
(10)
2Ph3M
2M + 3Ph Ph,
III
M = Sb, Bi.
Such reactions have been reported for derivatives
of antimony(III, V) and bismuth(III, V) in different
coordination states [8, 14, 15] and for other organo-
metallic compounds [16]. In the phenylation reactions
in question, the yield of compound III is 1 10%, but
sometimes attains 80 [with antimony(III, V) deriva-
tives] and 80 130% [with bismuth(III, V) derivatives].
The II/III yield ratio which measures the selectivity
of C-phenylation of ester I for Sb(III, V) derivatives
is always higher than for Bi(III, V) derivatives. Penta-
valent antimony and bismuth derivatives Ph3M(OAc)2
are always preferred over corresponding trivalent
derivatives Ph3M.
The reactions in oxygen were performed in a si-
milar way. The reactions in air were performed in
plugged ampules, and the solutions were not degassed.
ACKNOWLEDGMENTS
The work was financially supported by the Uni-
versitety Rossii Program (project no. 992839) and the
Integratsiya Federal Program (State Contract A 0047).
REFERENCES
EXPERIMENTAL
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Volatile products were analyzed by GLC on an
LKhM-80 chromatograph, flame-ionization detector,
column 100 cm, packing 15% Apieson-L on Chro-
maton N-AW, oven temperature 120 220 C, carrier
gas helium.
2. Finet, J.-P., Ligand Coupling Reactions with Hetero-
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3. Asano, R., Moritani, I., Fujiwara, Y., and Teranishi, S.,
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2911.
Ph3Bi and Ph3Sb were prepared as described in
[11, 17]. Ph3Bi(OAc)2 and Ph3Bi(O2CEt)2 were pre-
4. Kawamura, K., Kikukawa, K., Takagi, M., and
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 72 No. 10 2002