Palladium(II)-catalyzed phenylation of unsaturated compounds using phenylantimony chlorides under air

Article abstract of DOI:10.1016/S0022-328X(98)00974-7

Diphenylantimony chloride and phenylantimony dichloride, mainly the former, react smoothly with alkenes in acetonitrile at r.t. in the presence of a catalytic amount of Pd(OAc)₂ under air to afford the corresponding phenylated alkenes (Heck-type reaction). The addition of AgOAc as reoxidant is not necessary for this reaction in sharp contrast to similar reactions using triarylstibines. The oxygen absorption is confirmed in this catalytic reaction and the reaction does not proceed catalytically in palladium(II) under inert gases, such as nitrogen or argon. Even under air the addition of a radical scavenger stopped the reaction. The regeneration of PhPdOAc species from Ph₂SbCl, HPdOAc species and oxygen is proposed as a key step in the catalytic cycle where oxygen-containing radical species might be present as intermediates.

Full text of DOI:10.1016/S0022-328X(98)00974-7

Journal of Organometallic Chemistry 574 (1999) 3–10
Palladium(II)-catalyzed phenylation of unsaturated compounds using
phenylantimony chlorides under airꢀ
Kazutaka Matoba, Shin-ichi Motofusa, Chan Sik Cho, Kouichi Ohe, Sakae Uemura *
Department of Energy and Hydrocarbon Chemistry, Graduate School of Engineering, Kyoto Uni6ersity, Sakyo-ku, Kyoto 606-8501, Japan
Received 25 April 1998
Abstract
Diphenylantimony chloride and phenylantimony dichloride, mainly the former, react smoothly with alkenes in acetonitrile at
r.t. in the presence of a catalytic amount of Pd(OAc)2 under air to afford the corresponding phenylated alkenes (Heck-type
reaction). The addition of AgOAc as reoxidant is not necessary for this reaction in sharp contrast to similar reactions using
triarylstibines. The oxygen absorption is confirmed in this catalytic reaction and the reaction does not proceed catalytically in
palladium(II) under inert gases, such as nitrogen or argon. Even under air the addition of a radical scavenger stopped the reaction.
The regeneration of PhPdOAc species from Ph2SbCl, HPdOAc species and oxygen is proposed as a key step in the catalytic cycle
where oxygen-containing radical species might be present as intermediates. © 1999 Elsevier Science S.A. All rights reserved.
Keywords: Antimony; Palladium; Oxygen; Heck reaction
1. Introduction
course of further studies, they found that the above
phenylation reaction of alkenes proceeded also catalyti-
cally in Pd(OAc)2, but without AgOAc, when diphenyl-
antimony chloride and phenylantimony dichloride were
employed in lieu of triphenylstibine. This paper reports
here on the details of these reactions as one of the CꢀC
bond forming reactions using organoantimony com-
pounds [4–8] together with some mechanistic consider-
ations on the reaction pathway. It is worth noting that
pentavalent phenylantimony compound (Ph5Sb) reacted
with allyl acetate or allyl phenyl ether to afford allyl-
benzene in the presence of a catalytic amount of a
transition metal salt such as Pd(PPh3)4 or Pd(OAc)2 [9].
The chemistry of organoantimony compounds has
been developed and the potentiality of such compounds
in organic synthesis is currently increasing [1]. The
authors have recently reported [2] that triarylstibines
(Ar3Sb) reacted with enones and enals in the presence
of a catalytic amount of Pd(OAc)2 together with the
reoxidant AgOAc to afford the conjugate addition
products (the formal hydroarylated compounds to an
olefinic part) in good yield, while similar reactions
proceeded even in the absence of AgOAc when diaryl-
antimony chlorides and arylantimony dichlorides were
used. They have also disclosed that triphenylstibine
reacted with several alkenes other than enones and
enals to give the corresponding phenylated alkenes via
the so-called Heck-type reaction [3] under the same
conditions (with AgOAc and cat. Pd(OAc)2) [2]. In the
2. Results and discussion
2.1. Pd(II)-catalyzed phenylation of unsaturated
compounds
ꢀ Dedicated to the memory of the late Professor Rokuro Okawara.
* Corresponding author. Tel.: +81-75-753-5687; fax: +81-75-753-
5697; e-mail: uemura@scl.kyoto-u.ac.jp.
When 2-propen-1-ol (allyl alcohol) (1a) was treated
with 1.2 equimolar amounts of diphenylantimony chlo-
0022-328X/99/$ - see front matter © 1999 Elsevier Science S.A. All rights reserved.
PII: S0022-328X(98)00974-7

4
K. Matoba et al. / Journal of Organometallic Chemistry 574 (1999) 3–10
Scheme 1.
ride (2), prepared in situ from Ph3Sb:SbCl3 (2:1) ac-
cording to the literature method [10], in the presence of
a catalytic amount of Pd(OAc)2 (0.1 equimolar amount)
at 25°C for 24 h under air, 0.73 equimolar amounts of
3-phenylpropanal (3a) were obtained (73% yield on the
basis of the amount of 1a employed) (Scheme 1). When
an excess amount of 1a (five equimolar amounts) was
employed, the yield of 3a was 1.15 equimolar amounts
and less than the amount of 2 employed (1.2 equimolar
amounts), showing that only one phenyl group out of
the two of 2 was used in this reaction. At shorter
reaction times than 24 h, the yield became lower. The
formation of 3a, not 3-phenyl-2-propen-l-ol, by Heck-
type phenylation of 1a has been known (Scheme 2) [3].
Optimum reaction conditions for this phenylation reac-
tion were examined by using 1a as a substrate (Table 1).
In respect to the amount of catalyst, the best result was
obtained when 3 mol% Pd(OAc)2 was used. In the
reaction using either 10 or 1 mol% Pd(OAc)2, the
product yield was lower. As a solvent, acetonitrile
(CH3CN) and tetrahydrofuran (THF) were revealed to
be the solvent of choice. The product yield was much
lower in methanol and acetone. The reaction proceeded
smoothly at 25°C, while either at lower (0°C) or higher
(50°C) temperature, the product yield decreased consid-
erably. Thus, it was decided to apply to other alkenes
the reaction conditions using 3 mol% of Pd(OAc)2 and
acetonitrile as a solvent at 25°C under air.
From various alkenes, such as 1a, 3-buten-2-ol (1b),
2-methyl-2-propen-1-ol (1c), 2-buten-1-ol (1d), allyl ac-
etate (1h), 3-acetoxy-1-butene (1i), styrene (1m), h-
methylstyrene (1n), i-methylstyrene (1o), allylbenzene
(1p), acrylonitrile (1q) and methyl acrylate (1r), the
corresponding phenylation products were produced in
good to excellent yield (Table 2, runs 1–4, 8, 9 and
13–18). Each reaction was stopped when the amount of
phenylation product did not increase more by GLC
monitoring. On the other hand, from 3-methyl-2-buten-
1-ol (1e), cinnamyl alcohol (1f) and 2-cyclohexen-1-ol
(1g), the corresponding products were obtained only in
low yield (runs 5–7), while the formation of phenylated
products was not observed from 1-acetoxy-2-cyclohex-
ene (1j) and 1-acetoxy-3-methyl-2-butene (1k) (runs 10
and 11). From allyl phenyl ether (1l) an isomeric mix-
ture of two phenylated alkenes [(3l1), (3l2)] was ob-
tained (run 12). When h,i-unsaturated ketone,
3-buten-2-one (1s), was used, the expected phenyl-sub-
stituted product (4-phenyl-3-buten-2-one) was not
formed, but the product (3b) due to a formal Michael-
type conjugate addition of benzene to an alkene part
was produced as we have already noted in acetic acid as
solvent [2] (run 19). The formation of a slight amount
of biphenyl (B10%; one equimolar amount of biphenyl
to Ph2SbCl corresponds to 100%) and white precipitates
(described below) were observed in all cases. When the
reaction of two equimolar amounts of reactive sub-
strate 1r with one equimolar amount of Ph2SbCl was
carried out, 1.17 equimolar amounts of 3r were ob-
tained (58.5% yield on the basis of 1r), showing that, in
this case, a slightly more than one phenyl group out of
the two of 2 were transferred to 1r.
All the above described reactions were carried out
under air. However, the different result was obtained
when the reaction was carried out under nitrogen.
Thus, when 1a was treated with 2 in acetonitrile in the
presence of 3 mol% of Pd(OAc)2 at 25°C for 24 h under
nitrogen atmosphere, 3a was obtained only in 1.6%
yield (Table 3). A similar catalytic reaction under oxy-
gen afforded the product 3a in 87% yield with 6% yield
of biphenyl, and therefore, it became clear that the
presence of oxygen was inevitable for this catalytic
reaction. Actually, when the amount of oxygen con-
sumed in the phenylation of 1a under oxygen was
measured, it was revealed that an equimolar amount of
oxygen to the phenylation product was consumed (see
Section 4). In the presence of a stoichiometric amount
of Pd(OAc)2 (one equimolar amount), on the other
hand, 3a was obtained in 79% yield together with
biphenyl (35% yield on the basis of Ph2SbCl) in spite of
the lack of oxygen. It was also revealed that even under
air the addition of a radical scavenger, galvinoxyl,
prevented the reaction almost completely. The result
indicated that a free radical species may be involved in
this catalytic phenylation reaction under air.
As to the palladium catalysts, palladium(0) com-
plexes, such as tris(dibenzylideneacetone)dipalladium
and tetrakis(triphenylphosphine)palladium were inac-
tive. Even with Pd(OAc)2 no reaction occurred, when
triethylamine was added in the reaction system, the
addition of which being known to give a naked palla-
dium(0) species (Table 3) [4]. These results show that
Pd(0) is not effective for this reaction.

K. Matoba et al. / Journal of Organometallic Chemistry 574 (1999) 3–10
5
Scheme 2.
When phenylantimony dichloride (PhSbCl2), pre-
pared in situ from one equimolar amount of Ph3Sb and
two equimolar amounts of SbCl3 according to the same
method for Ph2SbCl [10], was reacted with an equimo-
lar amount of 1a under the above described optimum
conditions (with 3 mol% Pd(OAc)2 in acetonitrile at
25°C for 24 h under air), the yield of product 3a was
only 9%. Even by use of 10 mol% of the catalyst the
product yield was 39%. These results show that a
phenyl transfer ability is quite low in the case of
PhSbCl2 compared with Ph2SbC1 (2) in accord with the
evidence shown above that a transfer of more than one
phenyl group from 2 is quite slow.
Diphenylbismuth chloride (an analog of Ph2SbCl),
prepared from Ph3Bi and BiCl3 [11], was also applied to
this reaction. Table 4 summarizes the results of the
reactions with several substrates such as allyl alcohol
(1a), allyl acetate (1h) and allylbenzene (1p), where only
in the case of 1a, the corresponding phenylation
product was obtained. Compared with the case of
Ph2SbCl, much more biphenyl was produced when
Ph2BiCl was used, in accord with a report of a facile
formation of biphenyl from Ph2BiC1 [4]. Although
Ph2BiC1 was effective for phenylation of 1a, the pheny-
lation did not proceed well with many other arylmetal
chlorides, such as Ph2TlCl, Ph3SnC1 and Ar2TeCl2
under these reaction conditions. Thus, by use of
Ph2TlCl, only a trace amount of the corresponding
phenylation product was detected by GLC together
with 6% of biphenyl. In the case of Ph3SnCl, the
amount of the detected phenylation product was equal
to that of Pd(OAc)2 employed and biphenyl was not
detected by GLC, while in the case of Ar2TeCl2 no
products were detected.
2.2. Plausible reaction pathway
The active species of a Heck reaction has been gener-
ally accepted as a phenylpalladium species, and actually
Russell and co-workers have recently reported that
aromatic protons of the phenyl on palladium appeared
at 7.11 and 6.66 ppm [12]. On the other hand, the
protons of the phenyl moiety attached to antimony
usually appeared in the range 7.3–8.3 ppm [13] and are
distinguishable from the protons of the phenyl moiety
on palladium. The NMR spectroscopic studies were
carried out to know whether oxygen is needed in the
step of the formation of a phenylpalladium species or
not. The proton NMR spectrum (CDCl3) of the oil,
prepared by keeping a mixture of Ph3Sb (two equimolar
amounts) and SbCl3 (one equimolar amount) at 25°C
for 5 h, showed large multiplet peaks at 7.64 (2H) and
7.43 (3H) ppm together with small multiplet peaks at
7.88 and 7.58 ppm, those at 7.45 and 7.34 ppm and
those at 8.23 and 7.53 ppm. The former large peaks
correspond to Ph2SbCl, while the latter three small
peaks correspond to PhSbCl2, Ph3Sb and Ph3SbCl2,
respectively [13]. When Pd(OAc)2 (0.25 equimolar
amounts) was added to the CDCl3 solution of this oil
(mainly Ph2SbCl) under air, two new peaks appeared at
7.04 and 6.72 ppm, probably due to the formation of a
phenylpalladium species. Even when a completely
deaerated CDCl3 solution of Ph2SbCl (one equimolar
amount) was added to Pd(OAc)2 (0.25 equimolar
amounts) in an NMR tube under nitrogen, the NMR
spectrum of the resultant yellow solution showed sig-
nals of the corresponding aromatic protons of the
phenyl on palladium. Therefore, it is clear that oxygen
does not play a role in producing a phenylpalladium
species.
Table 1
Palladium(II)-catalyzed phenylation of allyl alcohol (1a) with
Ph2SbCl under various conditionsa
Pd(OAc)2
(mol%)
Solvent
Temperature (°C) Yield of 3ab (%)
10
3
1
3
3
10
1
10
10
10
10
CH3CN 25
CH3CN 25
CH3CN 25
73
94
80
50
65
79
80
60
44
23
10
CH3CN
0
CH3CN 50
THF
THF
25
25
By considering the above 1H-NMR spectral data
together with the necessity and consumption of oxygen
in this reaction, a plausible catalytic reaction pathway
for phenylation is presented in Scheme 3. First, a
phenylpalladium species [PhPd(OAc)] (4), produced by
transmetallation between diphenylantimony chloride (2)
and Pd(OAc)2, adds to an alkene (1) to afford an
Toluene 25
Acetone 25
AcOH
MeOH
25
25
a Ph3Sb (0.8 mmol), SbCl3 (0.4 mmol), 1a (1.0 mmol), solvent (10
ml), at 25°C.
b Determined by GLC on the basis of 1a.

6
K. Matoba et al. / Journal of Organometallic Chemistry 574 (1999) 3–10
Table 2
Palladium(II)-catalyzed phenylation of alkenes with Ph2SbCla
Run Alkene
1
Reaction Product
time (h)
Yieldb (%) Run Alkene
Reaction Product
time (h)
Yieldb (%)
40
21
94(91)
12
8
2
3
23
44
58(48)
89(67)
33 (E/
Z=15/85]c
13
14
19
72
100
4
24
58(42)
62
5
6
24
24
100
6
(12)
15
16
17
18
19
24
6
90(76)
71
Trace
7
13(11)
64
9
(100) [E/
Z=80/20]c
8
92(74)
72(63)
100(100)
62
9
10
9
10d
–
11d
–
a Ph3Sb (0.8 mmol), SbCl3 (0.4 mmol), alkene (1.0 mmol), Pd(OAc)2 (3 mol%), CH3CN (10 ml), at 25°C.
b GLC yield on the basis of alkene employed. Isolated yield is shown in parentheses.
c E/Z ratio was determined by GLC and 1H-NMR.
d Pd(OAc)2 (0.1 mmol, 10 mol%) was used.
alkylpalladium species (5). A b-hydride elimination
from 5 gives the product (3) and a hydridopalladium
species (6). This pathway from 4 to 6 has already been
well-established in a Heck reaction. Species 6 is ordi-
narily known to give palladium(0) and acetic acid by
reductive elimination and the phenylation reaction does
not proceed any more without a reoxidant. In this
catalytic phenylation, however, species 4 should be
regenerated by participation of oxygen as the reaction
does not proceed catalytically in the absence of oxygen.
The speculative process of this regeneration step is
shown in Scheme 4 on the basis of oxygen uptake in the
reaction as well as the presence of a free radical species.
First and most importantly, antimony has a hyperva-

K. Matoba et al. / Journal of Organometallic Chemistry 574 (1999) 3–10
7
Table 3
The effect of atmosphere and palladium catalystsa
Run
Catalyst (mol%)
Atmosphere
Additive
Yield (%)b
3-Phenylpropanal (3a)
Biphenyl
1
2
3
4
5
6
7
8
9
Pd(OAc)2 (3)
Pd(OAc)2 (3)
Pd(OAc)2 (100)
Pd(OAc)2 (3)
Pd(OAc)2 (3)
Pd2(dba)3 (10)
Pd(PPh3)4 (10)
Pd(OAc)2 (10)
–
Air
N2
N2
–
–
–
–
94
1.6
79
87
Trace
0
0
0
0
12
13
35
6
Trace
8
16
0
0
O2
Air
Air
Air
Air
Air
Galvinoxylc
–
–
Et3Nd
–
a Ph3Sb (0.8 mmol), SbCl3 (0.4 mmol), 1a (1.0 mmol), solvent (10 ml), at 25°C.
b Determined by GLC on the basis of 1a and 2, respectively.
c Galvinoxyl (5 mol%) was added.
d Triethylamine (2.0 mmol) was added.
lent nature; a co-ordination number of SbCl3 is 8, while
that of PhSbCl2 is 5, as shown by X-ray analysis [14].
Ph2SbCl should also be a hypervalent compound. Spe-
cies 6 can be co-ordinated by 2 mol of Ph2SbCl to
provide a complex A in which the electron density of
the antimony atom becomes lower than that of the free
Ph2SbCl. Therefore, the antimony atom of the complex
A can interact more easily with oxygen’s lone pair. The
co-ordination of oxygen is followed by homolytic
fission of the SbꢀC1 bond because of the radical char-
acter of oxygen. A chlorine atom abstracts the hydro-
gen attached to the neighboring Pd atom, and both
HCl and biradical species are generated. After the
intramolecular phenyl transfer, the biradical species
reacts with 2 to generate complex B and PhSbO2, the
latter of which being a polymeric compound and hardly
soluble in all organic solvents [15]. The formation of
white to grey precipitates was always observed after the
reaction. In spite of several attempts to characterize
these precipitates using IR, MS, EPMA, XRD and the
combustion analysis (see Section 4), however, the exact
nature of them is not yet clear; probably a mixture of
PhSbO2, PhSb(OH)Cl, PhSbCl2 and so on.
3. Conclusion
In conclusion, diphenylantimony chloride reacted
with many alkenes in the presence of a catalytic amount
of palladium(II) acetate under air to afford the corre-
sponding Heck-type phenylated products, while the re
activity of phenylantimony dichloride was much lower.
The presence of oxygen is inevitable for this cataly-
tic reaction and a phenylpalladium species might be
reproduced from a hydridopalladium species via oxy-
gen participating radical pathway. The reaction seemed
to be characteristic for Ph2SbCl, because the reac-
tion did not proceed catalytically with many other
similar chlorides of the corresponding Group 13–16
elements except for the combination of Ph2BiCl and
allyl alcohol.
Table 4
Palladium(II)-catalyzed phenylation with Ph2BiCla
Alkene Catalyst
(mol%)
Yield (%)
Phenylation productb Biphenylc
1a
1h
1p
1a
1a
Pd(OAc)2 (10) 3a 57 70
Pd(OAc)2 (10) 3h
Pd(OAc)2 (10) 3p
0
0
19
54
51
5
Pd(OAc)2 (3)
–
3a 61
3a
0
a Ph2BiCl (1.2 mmol), alkene (1.0 mmol), CH3CN (10 ml), at 25°C,
24 h.
b Isolated yield.
c Determined by GLC on the basis of Ph2BiCl.
Scheme 3.

8
K. Matoba et al. / Journal of Organometallic Chemistry 574 (1999) 3–10
Scheme 4.
4. Experimental
prepared by the known methods, respectively. Ph3SnCl
was commercially available. All allylic alcohols, allylic
acetates and other unsaturated compounds were com-
mercial products except for 3-acetoxy-1-butene (1i),
3-acetoxy-1-cyclohexene (1j) and 4-acetoxy-2-methyl-2-
butene (1k), which were synthesized by acylation of the
corresponding alcohols. All transition metal salts were
commercial products, except for [Pd(PPh3)4], which was
prepared by a known method [18].
1H- and 13C-NMR spectra were measured on JEOL
EX-400 and JEOL JNM-GSX270 spectrometers for
solutions in CDCl3 with Me4Si as an internal standard.
Melting points were determined on a Yanaco MP-J3
micro-melting point apparatus and uncorrected. MS
spectra were obtained on a Shimadzu QP-5000S spec-
trometer at an ionizing voltage of 70 eV. GLC analyses
were carried out with Shimadzu GC-14A instrument
equipped with a CBP 10-S25-050 (Shimadzu, fused
silica capillary column, 0.33 mm×25 m, 5.0 mm film
thickness) column using helium as carrier gas. GLC
yields were determined using dibenzyl as an internal
standard. Analytical thin layer chromatographies
(TLC) were performed with silica gel 60 Merck F-254
plates. Column chromatographies on SiO2 were per-
formed with Wakogel C-300. Elemental analyses were
performed at the Microanalytical Center of Kyoto Uni-
versity. The electron probe microanalysis (EPMA) was
performed with JEOL X-ray microanalyzer JXA-840A
instrument. For ion chromatography and inductively
coupled plasma (ICP), Dionex Co. (Tokyo), Dx-500
type and Seiko Instruments and Electronics Ltd., SPS
1700VR type were employed, respectively. X-ray pow-
der diffraction (XRD) data were obtained on MAC
Science Co. (Tokyo), MXP-18 system using Cu–Kh
radiation and an energy dispersive detector.
4.2. Reaction procedure
4.2.1. General procedure for Pd(II)-catalyzed reaction
of unsaturated compounds with diphenylantimony
chloride
Diphenylantimony chloride (1.2 mmol) was prepared
in situ by stirring triphenylstibine (0.8 mmol) and anti-
mony(III) chloride (0.4 mmol) in the absence of solvent
for 5 h at 25°C [10]. Then, a solution of unsaturated
compound (1 mmol) and palladium(II) acetate (6.9 mg,
0.03 mmol) in acetonitrile (10 ml) was added to the
above prepared Ph2SbCl and the mixture was stirred at
25°C for an appropriate time. The precipitated white to
grey solids were filtered off and the filtrate was poured
into brine (30 ml) and extracted with diethyl ether (30
ml). The organic extract was washed with water and
dried over anhydrous MgSO4. Removal of the solvent
under reduced pressure usually left an almost colorless
oil, which was separated and purified by column chro-
matography using ethyl acetate/hexane mixture as an
eluent to give the Heck-type product. For obtaining
GLC yield, a similar reaction was carried out in the
presence of an appropriate amount of dibenzyl as an
internal standard. The yield of the precipitated solid
was usually around 150 mg. All the products were
known compounds and only 1H-NMR spectroscopic
data are shown below except for the compounds 3b, 3d,
4.1. Materials
Commercially available organic and inorganic com-
pounds were used without further purification.
Diphenylantimony chloride (2) was prepared in situ by
the known disproportionation method between
triphenylstibine and antimony(III) chloride [10].
Ph2BiCl [11], Ph2TlCl [16] and Ar2TeCl2 [17] were

K. Matoba et al. / Journal of Organometallic Chemistry 574 (1999) 3–10
9
3h, 3m, 3n, 3q and 3r, which are commercial products.
3-Phenylpropanal (3a): 91% yield; an oil; H-NMR
containing the above prepared Ph2SbCl and the flask
was deaerated and then filled with oxygen. A syringe
filled with 50 ml of oxygen was connected to the flask in
which the reaction was carried out by adding solution
of allyl alcohol (1a) (58.1 mg, 1 mmol) in acetonitrile
(10 ml) under stirring. After 2 h, the 18 ml of oxygen in
the syringe was consumed, which corresponds to 0.74
mmol (25°C, 1 atm) and the oxygen consumption did
not increase any more. The GLC yield of 3-phenyl-
propanal (3a) was 72% (0.72 mmol).
1
l=2.78 (2H, td, J=7.7, 1.4 Hz), 2.97 (2H, t, J=7.7
Hz), 7.18–7.30 (5H, m) and 9.83 (1H, t, J=1.4 Hz).
2-Methyl-3-phenylpropanal (3c): 67% yield; an oil;
1H-NMR l=1.09 (3H, d, J=6.9 Hz), 2.60 (1H, dd,
J=12.6, 7.8 Hz), 2.68 (1H, m), 3.09 (1H, dd, J=12.6,
5.0 Hz), 7.16–7.33 (5H, m) and 9.72 (1H, d, J=1.4
Hz).
1
3-Methyl-3-phenylbutanal (3e): 12% yield; an oil; H-
NMR l=1.45 (6H, s), 2.66 (2H, d, J=3.0 Hz), 7.20–
7.39 (5H, m) and 9.49 (1H, t, J=3.0 Hz).
3-Phenylcyclohexanone (3g): 11% yield; an oil; H-
4.2.4. Attempts to characterize the precipitates formed
after the reaction
1
NMR l=1.74–1.92 (2H, m), 2.07–2.19 (2H, m), 2.32–
2.62 (4H, m), 2.96–3.04 (1H, m) and 7.21–7.37 (5H,
m).
The IR spectrum of the dried precipitates showed the
band at 457 cm−1, which can probably be assigned to
SbꢀO [19], as well as the bands corresponding to mono-
substituted phenyl group. The combustion analysis
showed H% 1.85, C% 24.72 and O% 11.80 and these
values were lower than those expected from PhSbO2
(H% 2.18, C% 31.22, O% 13.86). In the mass spectrum
analysis (FAB) the value of 365 was observed as a
parent peak and also the fragment peaks clearly showed
the presence of antimony considered from their ratio of
isotopes. Further, EPMA analysis of another lot
showed the presence of both antimony and chlorine
and the ICP analysis of Sb and the ion chromatography
analysis of Cl revealed them to be 63.8% and 8.96%,
respectively, the ratio of which being 2:1. The XRD
analysis showed that the precipitates were amorphous
and not crystalline inorganic compounds such as SbCl3
and Sb2O3.
(E)-3-Acetoxy-1-phenyl-1-butene (3i): 63% yield; an
1
oil; H-NMR l=1.41 (3H, d, J=6.6 Hz), 2.08 (3H, s),
5.53 (1H, dq, J=6.9, 6.6 Hz), 6.19 (1H, dd, J=16.0,
6.9 Hz), 6.60 (1H, d, J=16.0 Hz) and 7.24–7.40 (5H,
m).
(E)-Cinnamyl phenyl ether (3l1) and (E,Z)-phenyl-3-
phenyl-1-propenyl ether (3l2): 3l2 was isolated as an
E/Z mixture; 3l1 (a white solid as a pure form) was
1
identified by the H-NMR spectrum of a mixture of 3l1
and 3l2. 3l1: 1H-NMR l=4.71 (2H, d, J=5.9 Hz), 6.43
(1H, dt, J=16.1, 5.9 Hz), 6.74 (1H, d, J=16.1 Hz) and
6.94–6.99, 7.25–7.44 (10H, m). (E)-3l2: an oil; 1H-
4
NMR l=3.38 (2H, dd, J=7.5Hz and J=1.4 Hz),
5.54 (1H, dt, J=12.1, 7.5 Hz), 6.51 (1H, dt, J=12.1
4
Hz and J=1.4 Hz) and 6.97–7.09, 7.16–7.46 (10H,
1
m). (Z)-3l2: an oil; H-NMR l=3.58 (2H, dd, J=7.6
Hz and 4J=1.4 Hz), 5.04 (1H, td, J=7.6, 6.0 Hz), 6.50
4
(1H, dt, J=6.0 Hz and J=1.4 Hz) and 6.97–7.09,
Acknowledgements
7.16–7.46 (10H, m).
(E)-1,3-Diphenyl-1-propene (3p): an oil; 1H-NMR
l=3.55 (2H, d, J=6.2 Hz), 6.37 (1H, dt, J=15.9, 6.2
Hz), 6.47 (1H, d, J=15.9 Hz) and 7.21–7.37 (10H, m).
The authors would like to thank Dr Naoya Shige-
moto of Shikoku Research Institute Incorporated for
analysis of the precipitates by EPMA, ICP, ion chro-
matography and XRD.
4.2.2. The procedure for NMR spectroscopic study
In an NMR tube Pd(OAc)2 (1.89 mg, 8.4 mmol) was
placed under N2. The in situ prepared Ph2SbCl (10.6
mg, 34 mmol) was dissolved in degassed CDCl3 (0.5 ml),
and the mixture was deaerated by suction under cooling
with liquid nitrogen. The deaerated solution was then
added to Pd(OAc)2 in the NMR tube under N2, and the
1H-NMR analysis was carried out.
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10
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.