Rhodium-catalyzed conjugate addition of aryl- and alkenyl-stannanes to α,β-unsaturated carbonyl compounds

Article abstract of DOI:10.1016/S0040-4020(01)01128-0

The addition of aryl- or alkenyl-trimethylstannanes to α,β-unsaturated carbonyl compounds in the presence of a catalytic amount of a cationic rhodium complex ([Rh(cod)(MeCN)₂]BF₄) and water to afford the conjugate addition products in good yields was examined. It was observed that addition of water was necessary for the reaction to proceed smoothly. The aryl- or alkenyl-rhodium complex, which is generated by the transmetalation from the organotin compound, is considered to be the active catalytic species.

Full text of DOI:10.1016/S0040-4020(01)01128-0

TETRAHEDRON
Pergamon
Tetrahedron 58 (2002) 91±97
Rhodium-catalyzed conjugate addition of aryl- and
alkenyl-stannanes to a,b-unsaturated carbonyl compounds
Shuichi Oi,a,p Mitsutoshi Moro,a Hisanori Ito,a Yoshio Honma,a Sotaro Miyanob
and Yoshio Inouea,p
aDepartment of Materials Chemistry, Graduate School of Engineering, Tohoku University, Sendai 980-8579, Japan
bDepartment of Biomolecular Engineering, Graduate School of Engineering, Tohoku University, Sendai 980-8579, Japan
Received 15 October 2001; accepted 12 November 2001
AbstractÐThe addition of aryl- or alkenyl-trimethylstannanes to a,b-unsaturated carbonyl compounds in the presence of a catalytic amount
of a cationic rhodium complex ([Rh(cod)(MeCN)2]BF4) and water to afford the conjugate addition products in good yields was examined. It
was observed that addition of water was necessary for the reaction to proceed smoothly. The aryl- or alkenyl-rhodium complex, which is
generated by the transmetalation from the organotin compound, is considered to be the active catalytic species. q 2002 Elsevier Science Ltd.
All rights reserved.
1. Introduction
metalation with the arylstannanes, were assumed to be the
active species that actually adds to the aldehydes or
aldimines. During our investigations on the utilization of
this methodology, we realized that the conjugate addition
of aryl- or alkenyl-stannanes occurred in the cases where the
a,b-unsaturated carbonyl compounds were the substrates.13
Herein, we wish to report scope and limitation of the
rhodium-catalyzed conjugate addition reaction of organotin
compounds to a,b-unsaturated carbonyl compounds. The
reaction can be carried out under mild and neutral condi-
tions, and furthermore, not only a,b-unsaturated ketones,
but a,b-unsaturated esters and aldehydes were also shown
to undergo similar conjugate additions.
The conjugate addition of organometallic compounds to
a,b-unsaturated carbonyl compounds, which involves the
carbon±carbon bond formation at the b-position of the car-
bonyl compounds, is an important and useful method of
synthesizing b-substituted saturated carbonyl compounds.
Such reactions are typically carried out using organocopper
reagents, which are generated from the reaction between
copper salts and the corresponding organolithium or
Grignard reagents.1 Conjugate additions of organo-
aluminum2 and organoboron3 compounds, without a
catalyst, have also been reported. Furthermore, transition
metal-catalyzed conjugate addition reactions of main
group organometallic reagents are potentially useful in
terms of chemo-, regio-, and stereoselectivities, with a
possible extension into asymmetric systems using a
combination of appropriate catalysts. For example, nickel-
catalyzed conjugate addition of organoaluminum,4
organozinc,5 and organozirconium6 compounds, palladium-
2. Results and discussion
To optimize the reaction conditions, the reaction of
4-phenylbut-3-en-2-one (1a) with trimethylphenylstannane
(2a) was examined under various settings (Table 1).
Reactions were carried out in THF or CH2Cl2 as the solvent,
in the presence of 2 mol% cationic rhodium complex,
[Rh(cod)(MeCN)2]BF4, at room temperature for 20 h to
afford 4,4-diphenylbutan-2-one (3aa) in approximately
50% yields (entries 1 and 2). However, using toluene as
the solvent resulted in a lower yield of 41%, while using
acetonitrile as the solvent gave only 6% yield (entries 3 and
4). When the reaction was carried out at 608C in THF, a
higher yield of 3aa (86%) was observed for the reaction
time of 2 h (entry 5). The neutral chlorine-bridged dimer
complex, [RhCl(cod)]2, did not show good activity as
the cationic one affording the product in lower yield of
53% under similar conditions of 608C in THF for 2 h
(entry 6). The addition of phosphine ligands such as PPh3
catalyzed
conjugate
addition
of
arylmercury,7
arylantimony,8 and aryltin compounds,7,9 and rhodium-
catalyzed conjugate addition of aryl- or alkenyl-boronic
acids10 have been reported. Previously, we have demon-
strated that arylstannanes, in the presence of a cationic
rhodium complex as the catalyst, can add to aldehydes11
or to aldimines12 to afford the corresponding arylated
carbinols or amines, respectively. In these reactions, the
arylrhodium species, which was generated by the trans-
Keywords: conjugate addition; a,b-unsaturated carbonyl compound;
organotin compounds; thodium catalyst.
Corresponding authors. Tel.: 181-22-217-5876; fax: 181-22-217-5873;
e-mail: oishu@aporg.che.tohoku.ac.jp
p
0040±4020/02/$ - see front matter q 2002 Elsevier Science Ltd. All rights reserved.
PII: S0040-4020(01)01128-0

92
S. Oi et al. / Tetrahedron 58 (2002) 91±97
Table 1. Rhodium-catalyzed conjugate addition of 2a to 1a under various
reaction conditions
or 1,3-bis(diphenylphosphino)propane (dppp) to the
cationic complex also resulted in lower yields (entries 7±9).
Based on the high yield, as shown in Table 1 (entry 5),
similar conditions were employed for the reaction of methyl
vinyl ketone (1b) with 2a. However, despite the complete
consumption of the enone 1b, the conjugate adduct 3ba was
obtained in only an 18% yield (Table 2, entry 1), which can
be explained by the further reactions of the product stannyl
enol ether (vide infra) with the starting substrate enone 1b.
Thus, to immediately decompose the stannyl enol ether to
ketone 3ba, addition of protic species to the reaction was
examined. As shown in Table 2 (entries 2 and 4), the
addition of methanol or water was found to increase the
yields; optimally, the addition of an equimolar amount of
water afforded the desired product 3ba in a yield of 80%.
However, the addition of acetic acid did not show similar
enhancements (entry 3). In the case of 1a, the addition of
water similarly increased the yield from 86 to 98% (entries 5
and 6).
Entry
Solvent
Ligand
Temperature (8C)/time (h)
Yield (%)a
1
2
3
4
5
6b
7
8
9
THF
None
None
None
None
None
None
Rt/20
Rt/20
Rt/20
Rt/20
60/2
60/2
60/2
60/2
60/2
51
50
41
6
86
53
63
15
48
CH2Cl2
Toluene
CH3CN
THF
THF
THF
c
PPh3
PPh3
d
THF
THF
dpppc,e
Common reaction conditions: 1a (1.0 mmol), 2a (1.2 mmol), [Rh(cod)-
(MeCN)2]BF4 (0.02 mmol), solvent (1 mL), N2 atmosphere.
a
Isolated yield.
[RhCl(cod)]2 (0.01 mmol) was used as the catalyst.
b
c
L/Rhˆ1.
d
L/Rhˆ2.
Results of the conjugate addition between aryl- or alkenyl-
stannanes 2a±f and various a,b-unsaturated ketones
(enones 1a±l) are summarized in Table 3. Reactions
between trimethylphenylstannane (2a) and enones, includ-
ing cyclic enones, having mono- or di-substituted ole®nic
moieties (1a±j) proceeded smoothly to afford the corre-
sponding b-phenylated ketones 3aa±ja in good yields
(entries 1±10). Unsaturated products of the Heck type
were not observed for this series of reactions. In contrast,
the reactions involving hindered enones, such as 3-methyl-
pent-3-en-2-on (1k) and isophorone (1l) were sluggish; the
former afforded the product 3ka in a moderate yield of 37%,
even under a longer reaction time of 24 h (entry 11), and
the latter did not react under similar reaction conditions
(entry 12).
e
1,3-Bis (diphenylphosphino)propane.
Table 2. Effect of additive in conjugate addition of 2a to 1a or 1b
Entry
Enone 1
Additive
yield (%)a
1
2
3
4
5
6
1b
1b
1b
1b
1a
1a
None
MeOH
AcOH
H2O
None
H2O
18
63
0
80
86
98
Continuing with different stannanes, the reaction of 1a with
phenyltributylstannane (2b) resulted in a somewhat lower
yield of 70% (entry 13), while the reaction with tetra-
phenylstannane (2c) resulted in a yield of only 11% (entry
14), which can be attributable to the steric hindrance of
the phenylstannanes. Arylstannanes bearing an electron-
withdrawing or -donating group, such as p-¯uorophenyl-
trimethylstannane (2d) and p-methoxyphenyltrimethyl-
Reaction conditions: 1 (1.0 mmol), 2a (1.2 mmol), additive (1.0 mmol),
[Rh(cod)(MeCN)2]BF4 (0.02 mmol), THF (1 mL), 608C, 5 h (for 1b), 2 h
(for 1a), N2 atmosphere.
a
Isolated yield.
Table 3. Rhodium-catalyzed conjugate addition of organotin compounds 2 to a,b-unsaturated ketones 1
Entry
1
Enone 1
Stannane 2
Time (h)
2
Product
Yield (%)a
98
Ph-SnMe3 (2a)
2
3
2a
2a
5
5
80
88
4
2a
2
94

S. Oi et al. / Tetrahedron 58 (2002) 91±97
93
Table 3. (continued)
Entry
Enone 1
Stannane 2
Time (h)
2
Product
Yield (%)a
5
6
7
8
2a
60
85
85
79
2a
2a
2a
2
2
15
9
2a
2a
2a
2
5
93
91
37
10
11
24
12
13
2a
24
±
0
Ph-SnBu3 (2b)
2
2
2
3aa
3aa
70
11
68
14
15
1a
1a
Ph4Sn (2c)
p-FC6H4-SnMe3 (2d)
16
17
1a
p-MeOC6H4-SnMe3 (2e)
2
74
70
20
18
2f
20
45
19
20
2f
2f
20
20
23
0
±
Reaction conditions: 1 (1.0 mmol), 2 (1.2 mmol), water (18 mL, 1.0 mmol), [Rh(cod)(MeCN)2]BF4 (0.02 mmol), THF (1 mL), 608C, N2 atmosphere.
Isolated yield.
a
stannane (2e), reacted smoothly with 1a to afford the corre-
sponding conjugate adducts 3ad and 3ae in good yields of
68 and 74%, respectively (entries 15 and 16). Compara-
tively, the reactivities of alkenylstannanes appeared to be
lower than those of arylstannanes. The addition of styryl-
trimethylstannane (2f) to methyl vinyl ketone (1b) afforded
product 3bf in a good yield of 70% (entry 17), whereas
the additions to 3-methylbut-3-en-2-one (1c) and cyclo-
hexenone (1i) afforded products 3cf and 3if in moderate
yields of 45 and 23%, respectively (entries 18 and 19).

94
S. Oi et al. / Tetrahedron 58 (2002) 91±97
Table 4. Rhodium-catalyzed conjugate addition of 2a to a,b-unsaturated
esters 4 or aldehydes 6
hyde (6c) with 2a resulted in the conjugate adducts 7aa±ca
with yields of 52, 47, and 43%, respectively (entries 9±11).
As a note, in the cases of the aldehydes, conjugate addition
was predominantly observed, and the competing reaction of
1,2-addition was not detected.
Entry
1
Ester 4 or aldehyde 6
Product
Yield (%)a
66
In the presented reactions, an organorhodium species is
assumed to be the active intermediate, which is generated
by the transmetalation between the organotin compound and
the rhodium complex. The presumed reaction pathway is
shown in Scheme 1 (for simpli®cation, ligands of the
rhodium complexes not involved with the reaction are
omitted). As the initial step, the transmetalation of the
cationic rhodium complex (Rh1BF42) with organotin 2
2
3
75
71
produces the organorhodium intermediate
8
and
4
5
90
0
Me3SnBF4. Addition of 8 to the a,b-unsaturated carbonyl
compound 1 leads to the h3-oxa-p-allylrhodium complex 9,
which then reacts with Me3SnBF4 to afford stannyl enol
ether 10 and to regenerate the cationic rhodium complex.
NMR studies of the reaction mixture, in the absence of
water, indicated the formation of the corresponding
stannyl enol ether 10; furthermore, NOE experiments of
10 showed the preferential formation of the Z-isomer. The
stannyl enol ether 10 was easily hydrolyzed to afford
product 3.13a
±
6
7
68
54
To gain information on the reaction mechanism, the
reactivity of [Rh(cod)(CH3CN)2]BF4 toward trimethyl-
phenylstannane (2a) was studied. When 0.1 mmol of
[Rh(cod)(CH3CN)2]BF4 was treated with equimolar
amount of 2a and D2O in THF at 258C for 20 h, the stannane
2a was completely consumed and deuterized benzene
(44% yield, 78%-d) was formed. A control experiment
con®rmed that the stannane 2a was inert to water. The result
indicates the generation of a water-labile species from
[Rh(cod)(CH3CN)2]BF4 and the stannane 2a, which we
attribute to an unstable phenylrhodium species that should
decompose rapidly to give benzene. Interestingly, the
present conjugate addition reaction was carried out in the
presence of water and that indicate that the unstable
phenylrhodium species reacted with a,b-unsaturated car-
bonyl compounds faster than with water. Unfortunately,
we tried in vain to detect a peak corresponding to the
phenylrhodium species by 1H and 13C NMR measurements
of the reaction without water in THF-d8, which would be
caused by the instability of the species. A similar reaction
mechanism, which involves the generation of the organo-
rhodium intermediate, has been proposed by Miyaura et al.
in their studies of the rhodium-catalyzed conjugate
addition of arylboronic acid to a,b-unsaturated carbonyl
compounds.10c
8
9
57
52
10
11
47
43
Reaction conditions: 4 or 6 (1.0 mmol), 2a (1.2 mmol), water (18 mL,
1.0 mmol), [Rh(cod)(MeCN)2]BF4 (0.02 mmol), THF (1 mL), 608C, N2
atmosphere.
a
Isolated yield.
Unfortunately, the addition reaction between 1a and 2f was
not observed (entry 20).
As summarized in Table 4, the conjugate addition of
phenyltrimethylstannane (2a) to various a,b-unsaturated
esters and aldehydes were also examined. The conjugate
addition of 2a to a,b-unsaturated esters having mono- or
di-substituted ole®nic moieties (4a±d) proceeded smoothly
with good yields (entries 1±4). However, due to the steric
hindrance of the substituents, the reaction between the
a,b-unsaturated ester having trisubstituted ole®nic moiety
4e and 2a was not observed (entry 5). Reactions involving
endo- and exo-enlactones 4f±h as the substrate resulted in
acceptable yields (entries 6±8). For the cases involving
a,b-unsaturated aldehydes as the substrate, the reactions
of methacrolein (6a), crotonaldehyde (6b), and cinnamalde-
3. Conclusion
A highly ef®cient rhodium-catalyzed conjugate addition of
organotin compounds to a,b-unsaturated carbonyl
compounds was examined. It was shown that the presence
of water improved the reaction. An aryl- or alkenyl-rhodium
complex, which was generated by the transmetalation from
the organotin compound, is considered to be the active
catalytic species. Since the organotin compounds are inert
to many organic compounds, and the reaction can be

S. Oi et al. / Tetrahedron 58 (2002) 91±97
95
Scheme 1. Presumed reaction mechanism.
carried out under mild and neutral conditions, we believe
that the present reaction can be a useful methodology in the
synthesis of complicated compounds such as natural
products.
(62.5 MHz) d 207.4, 140.4, 128.0, 127.7, 125.6, 44.6,
29.5, 29.2.
4.1.3. 3-Methyl-4-phenylbutan-2-one (3ca).16 IR (neat)
1
2970, 2930, 1713, 1456, 1360, 1162, 740, 700 cm21. H
NMR (250 MHz) d 7.40±7.13 (m, 5H), 2.99 (dd, Jˆ13.3,
6.7 Hz, 1H), 2.83 (ddq, Jˆ7.5, 6.8, 6.7 Hz, 1H), 2.55 (dd,
Jˆ13.3, 7.5 Hz, 1H), 2.08 (s, 3H), 1.08 (d, Jˆ6.8 Hz, 3H).
13C NMR (62.5 MHz) d 212.0, 139.6, 128.9, 128.3, 126.2,
48.7, 38.8, 28.8, 16.2.
4. Experimental
4.1. General information
All reactions were carried out in Schlenk tubes under N2.
THF was dried over sodium/benzophenone ketyl, and
distilled before use. NMR spectra were recorded using
CDCl3 as the solvent. Elemental analyses were performed
by the Microanalytical Laboratory of the Institute for
Chemical Reaction Science, Tohoku University. Spherical
silica gel (40±100 mm, Kanto Chemical) was used for ¯ash
chromatography. The cationic rhodium complex,
[Rh(cod)(MeCN)2]BF4, was prepared as described.14 The
organotin compounds (2d±f) were prepared from the corre-
sponding Grignard reagents and trimethylstannyl chloride.15
4.1.4. 1,3,3-Triphenylpropan-1-one (3da).9 IR (KBr)
3040, 1680, 1600, 1500, 1380, 1265, 1219, 754,
1
700 cm21. H NMR (250 MHz) d 7.93 (d, Jˆ7.0 Hz, 2H),
7.58±7.41 (m, 3H), 7.38±7.15 (m, 10H), 4.83 (t, Jˆ7.3 Hz,
1H), 3.74 (d, Jˆ7.3 Hz, 2H). 13C NMR (62.5 MHz) d 210.2,
144.1, 137.1, 133.1, 128.6, 128.5, 128.1, 127.8, 126.4, 45.9,
44.7.
4.1.5. 1,3-Diphenylbutan-1-one (3ea). Mp 50±528C. IR
(KBr) 2961, 1680, 1598, 1497, 1444, 1204, 982, 759, 700,
1
690 cm21. H NMR (250 MHz) d 7.92 (d, Jˆ7.1 Hz, 2H),
7.56±7.39 (m, 3H), 7.33±7.17 (m, 5H), 3.51 (ddq, Jˆ8.3,
7.0, 5.9 Hz, 1H), 3.29 (dd, Jˆ16.3, 5.9 Hz, 1H), 3.17 (dd,
Jˆ16.3, 8.3 Hz, 1H), 1.34 (d, Jˆ7.0 Hz, 3H). 13C NMR
(62.5 MHz) d 199.0, 146.5, 132.9, 128.5, 128.4, 128.0,
126.8, 126.2, 47.0, 35.5, 21.8. Anal. Calcd for C16H16O:
C, 85.68; H, 7.19. Found: C, 85.60; H, 7.25.
4.1.1. Catalytic conjugate addition of organotin
compounds. To a mixture of 4-phenylbut-3-en-2-on (1a,
146 mg, 1.0 mmol) and [Rh(cod)(MeCN)2]BF4 (7.4 mg,
0.02 mmol) in THF (1 mL) were added trimethylphenyl-
stannane (2a, 289 mg, 1.2 mmol) and water (18 mL,
1.0 mmol), and stirred at 608C for 2 h. Et2O (20 mL) was
added to the reaction mixture and the resulting precipitate
was removed by ®ltration. The solvent was removed in
vacuo and the residue was puri®ed by ¯ash chromatography
(hexane/AcOEtˆ10:1) to yield 4,4-diphenylbutan-2-one
(3aa, 220 mg, 98%).8 Mp 58±608C. IR (KBr) 3022, 1720,
4.1.6. 4-Phenylheptan-2-one (3fa). IR (neat) 2978, 1730,
1
1604, 1501, 1460, 1362, 1170, 768, 707 cm21. H NMR
(250 MHz) d 7.31±7.15 (m, 5H), 3.13 (quint, Jˆ7.2 Hz,
1H), 2.71 (d, Jˆ7.2 Hz, 2H), 2.00 (s, 3H), 1.65±1.51 (m,
2H), 1.21±1.08 (m, 2H), 0.84 (t, Jˆ7.1 Hz, 3H). 13C NMR
(62.5 MHz) d 208.0, 144.5, 128.4, 127.4, 126.3, 50.9, 41.0,
38.7, 30.6, 20.5, 13.9. Anal. Calcd for C13H18O: C, 82.06; H,
9.53. Found: C, 81.66; H, 9.69.
1
1602, 1499, 1455, 1360, 1161, 755, 700 cm21. H NMR
(250 MHz) d 7.28±7.10 (m, 10H), 4.57 (t, Jˆ7.5 Hz, 1H),
3.14 (d, Jˆ7.5 Hz, 2H), 2.02 (s, 3H). 13C NMR (62.5 MHz)
d 206.7, 143.7, 128.5, 127.6, 126.3, 49.5, 45.9, 30.5.
4.1.7. 4-Phenylnonan-2-one (3ga).8 IR (neat) 2930, 1720,
4.1.2. 4-Phenylbutan-2-one (3ba).9 IR (neat) 3020, 2930,
1
1455, 1360, 1160, 759, 701 cm21. H NMR (250 MHz) d
1
1720, 1602, 1500, 1459, 1360, 1162, 750, 699 cm21. H
7.30±7.15 (m, 5H), 3.10 (quint, Jˆ7.9 Hz, 1H), 2.70 (d,
NMR (250 MHz) d 7.31±7.16 (m, 5H), 2.89 (t, Jˆ6.8 Hz,
2H), 2.77 (t, Jˆ6.8 Hz, 2H), 2.13 (s, 3H). 13C NMR
Jˆ6.8 Hz, 2H), 2.00 (s, 3H), 1.57 (brs, 2H), 1.20 (brs,

96
S. Oi et al. / Tetrahedron 58 (2002) 91±97
6H), 0.82 (t, Jˆ5.7 Hz, 3H). 13C NMR (62.5 MHz) d 207.9,
144.5, 128.3, 127.4, 126.2, 50.8, 41.2, 36.3, 31.6, 30.6, 27.0,
22.4, 13.9.
4.1.15. trans-3-Methyl-6-phenylhex-5-en-2-one (3cf). IR
(neat) 2971, 1712, 1494, 1450, 1360, 1241, 1166, 967,
742, 693 cm21 1H NMR (500 MHz) d 7.37±7.17 (m,
.
5H), 6.40 (d, Jˆ15.8 Hz, 1H), 6.12 (dt, Jˆ15.8, 7.2 Hz,
1H), 2.68±2.57 (m, 1H), 2.57±2.52 (m, 1H), 2.28±2.22
(m, 1H), 2.16 (s, 3H), 1.14 (d, Jˆ7.0 Hz, 3H). 13C NMR
(125 MHz) d 211.8, 137.3, 132.1, 128.5, 127.3, 127.2,
126.1, 47.1, 36.2, 28.4, 16.1. Anal. Calcd for C13H16O: C,
82.93; H, 8.57. Found: C, 82.53; H, 8.57.
4.1.8. 5-Methyl-4-phenylhexan-2-one (3ha). IR (neat)
2960, 1715, 1457, 1359, 1160, 700 cm21 1H NMR
.
(250 MHz) d 7.30±7.12 (m, 5H), 2.96±2.87 (m, 1H),
2.80±2.77 (m, 2H), 1.96 (s, 3H), 1.89±1.76 (m, 1H), 0.93
(d, Jˆ6.8 Hz, 3H), 0.74 (d, Jˆ6.8 Hz, 3H). 13C NMR
(62.5 MHz) d 209.0, 143.2, 128.2, 128.1, 126.2, 48.0,
47.5, 33.2, 30.5, 20.6, 20.2. Anal. Calcd for C13H18O: C,
82.06; H, 9.53. Found: C, 81.80; H, 9.38.
4.1.16. 3-(trans-2-Phenylethenyl)cyclohexan-1-one (3if).18
1
IR (neat) 3025, 2935, 1710, 1448, 966, 747, 694 cm21. H
NMR (400 MHz) d 7.36±7.17 (m, 5H), 6.39 (d, Jˆ16.0 Hz,
1H), 6.15 (dd, Jˆ16.0, 6.8 Hz,1H), 2.72±2.62 (m, 1H),
2.55±2.50 (m, 1H), 2.43±2.37 (m, 1H), 2.35±2.27 (m,
2H), 2.14±2.06 (m, 1H), 2.04±1.97 (m, 1H), 1.80±1.69
(m, 1H), 1.66±1.56 (m, 1H). 13C NMR (100 MHz) d
210.1,137.1, 132.9, 129.1, 128.5, 127.3, 126.1, 47.3, 41.9,
41.2, 31.6, 25.0.
4.1.9. 3-Phenylcyclohexan-1-one (3ia).8 IR (neat) 2930,
1
1703, 1601, 1499, 1452, 1201, 756, 699 cm21. H NMR
(250 MHz) d 7.42±7.20 (m, 5H), 3.02±2.96 (m, 1H),
2.96±2.36 (m, 4H), 2.18±2.05 (m, 2H), 1.88±1.73 (m,
2H). 13C NMR (62.5 MHz) d 211.0, 144.3, 128.7, 126.9,
126.6, 48.8, 44.7, 41.1, 32.7, 25.4.
4.1.10. 3-Phenylcyclopentan-1-one (3ja).9 IR (neat) 3029,
2962, 2893, 1746, 1603, 1495, 1454, 1402, 1282, 1136, 763,
700 cm21. 1H NMR (500 MHz) d 7.36±7.32 (m, 2H), 7.26±
7.23 (m, 3H), 3.45±3.38 (m, 1H), 2.67 (dd, Jˆ18.2, 7.5 Hz,
1H), 2.49±2.41 (m, 2H), 2.37±2.26 (m, 2H), 2.04±1.94 (m,
1H). 13C NMR (125 MHz) d 218.2, 143.1, 128.7, 126.7,
45.7, 42.2, 38.8, 31.1.
4.1.17. 3-Phenylpropanoic acid methyl ester (5aa).19 IR
(neat) 3027, 2951, 1738, 1495, 1453, 1436, 1365, 1257,
1
1196, 1162, 749, 700 cm21. H NMR (250 MHz) d 7.28±
7.18 (m, 5H), 3.68 (S, 3H), 2.95 (t, Jˆ8.1 Hz, 2H), 2.63 (t,
Jˆ7.7 Hz, 2H). 13C NMR (62.5 MHz) d 173.3, 143.5,
128.6, 127.6, 126.5, 51.7, 35.7, 30.9.
4.1.18. 2-Methyl-3-phenylpropanoic acid methyl ester
(5ba). IR (neat) 3028, 2951, 1737, 1496, 1454, 1362,
4.1.11. 3-Methyl-4-phenylpentan-2-one (3ka). IR (neat)
.
1
2965, 1710, 1495, 1452, 1359, 700 cm21
1H NMR
1254, 1166, 745, 701 cm21. H NMR (250 MHz) d 7.34±
(250 MHz) d 7.33±7.15 (m, 5H), 3.05±2.85 (m, 1H),
2.81±2.65 (m, 1H), 2.19 (s, 3H), 1.21 (d, Jˆ6.8 Hz, 3H),
0.85 (d, Jˆ6.8 Hz, 3H). 13C NMR (62.5 MHz) d 213.0,
144.6, 128.4, 127.3, 126.3, 54.0, 42.7, 29.2, 20.6, 16.0.
Anal. Calcd for C12H16O: C, 81.77; H, 9.15. Found: C,
81.65; H, 9.34.
7.13 (m, 5H), 3.58 (s, 3H), 3.02 (q, Jˆ6.2 Hz, 1H),2.80±
2.59 (m, 2H), 1.15 (s, 3H). 13C NMR (62.5 MHz) d 176.5,
139.3, 128.9, 128.3, 126.3, 51.5, 41.4, 39.6, 16.7. Anal.
Calcd for C11H14O2: C, 74.13; H, 7.92. Found: C, 73.81;
H, 7.56.
4.1.19. 3-Phenylbutanoic acid ethyl ester (5ca). IR (neat)
4.1.12. 4-(4-Fluorophenyl)-4-phenylbutan-2-one (3ad).
IR (neat) 3035, 1715, 1601, 1509, 1360, 1222, 1160, 840,
2965, 1733, 1263, 1175, 1020, 700 cm21 1H NMR
.
(250 MHz) d 7.46±7.16 (m, 5H), 4.07 (q, Jˆ7.1 Hz, 2H),
3.28 (ddq, Jˆ8.0, 7.1, 7.0 Hz, 1H), 2.60 (dd, Jˆ15.0,
7.0 Hz, 1H), 2.53 (dd, Jˆ15.0, 8.0 Hz, 1H), 1.30 (d,
Jˆ7.1 Hz, 3H), 1.17 (t, Jˆ7.1 Hz, 3H). 13C NMR
(62.5 MHz) d 172.3, 145.7, 128.4, 126.3, 126.2, 60.2,
43.0, 36.5, 21.8, 14.1. Anal. Calcd for C12H16O2: C, 74.97;
H, 8.39. Found: C, 74.87; H, 8.30.
1
700 cm21. H NMR (250 MHz, CDCl3) d 7.29±7.14 (m,
7H), 6.92 (t, Jˆ6.5 Hz, 2H), 4.57 (t, Jˆ7.5 Hz, 1H), 3.14
(d, Jˆ7.5 Hz, 2H), 2.05 (s, 3H). 13C NMR (62.5 MHz) d
206.4, 161.3(d, Jˆ972.8 Hz), 143.6, 139.6, 129.1, 129.0,
128.6, 127.5, 126.5, 115.4, 115.1, 49.6, 45.1, 30.5. Anal.
Calcd for C16H15O2F: C, 79.32; H, 6.14. Found: C, 79.48;
H, 6.36.
4.1.20. 3,3-Diphenylpropanoic acid methyl ester (5da).
IR (neat) 3030, 2959, 1740, 1497, 1451, 1260, 1160, 740,
700 cm21. 1H NMR (250 MHz) d 7.31±7.14 (m, 10H), 4.55
(t, Jˆ8.0 Hz, 1H), 3.57 (s, 3H), 3.06 (d, Jˆ8.0 Hz, 2H). 13C
NMR (62.5 MHz) d 172.2, 143.4, 128.5, 127.6, 126.5, 51.6,
46.9, 40.5. Anal. Calcd for C16H16O2: C, 79.95; H, 6.71.
Found: C, 79.96; H, 6.95.
4.1.13. 4-(4-Methoxyphenyl)-4-phenylbutan-2-one (3ae).9
IR (neat) 2960, 2940, 1720, 1605, 1506, 1250, 838,
1
700 cm21. H NMR (250 MHz) d 7.29±7.11 (m, 7H), 6.95
(d, Jˆ6.6 Hz, 2H), 4.53 (t, Jˆ7.6 Hz, 1H), 3.73 (s, 3H), 3.13
(d, Jˆ7.6 Hz, 2H), 2.04 (s, 3H). 13C NMR (62.5 MHz) d
206.8, 158.0, 144.2, 135.9, 128.6, 128.5, 127.5, 126.3,
113.9, 55.1, 49.8, 45.2, 38.7, 30.5.
4.1.21. 4-Phenyltetrahydrofuran-2-one (5fa). IR (neat)
1
4.1.14. trans-6-Phenylhex-5-en-2-one (3bf).17 IR (neat)
3026, 1715, 1598, 1492, 1439, 1364, 1160, 1070,
2911, 1775, 1604, 1496, 1169, 1019, 700 cm21. H NMR
(250 MHz) d 7.41±7.22 (m, 5H), 4.70±4.23 (m, 2H), 3.79
(qui, Jˆ8.4 Hz, 1H), 2.99±2.62 (m, 2H). 13C NMR
(62.5 MHz) d 176.47, 139.47, 129.20, 127.78, 126.77,
74.10, 41.15, 35.76. Anal. Calcd for C10H10O2: C, 74.06;
H, 6.21. Found: C, 74.02; H, 6.22.
967, 749, 694 cm21 1H NMR (400 MHz) d 7.34±7.18
.
(m, 6H), 6.41 (d, Jˆ15.8 Hz, 1H), 6.19 (dt, Jˆ15.8,
6.9 Hz, 1H), 2.61 (t, Jˆ7.15 Hz, 2H), 2.48 (td, Jˆ7.15,
6.9 Hz, 2H), 2.17 (S, 3H). 13C NMR (100 MHz) d
182.0, 137.5, 130.8, 128.9, 128.5, 127.1, 126.1, 43.2, 30.1,
27.2.
4.1.22. 4-Phenyltetrahydropyran-2-one (5ga). IR (neat)

S. Oi et al. / Tetrahedron 58 (2002) 91±97
97
2933, 1730, 1495, 1456, 1260, 1157, 1074, 762, 701 cm21
.
2. (a) Bernady, K. F.; Floyd, M. B.; Poletto, J. F.; Weiss, M. J.
J. Org. Chem. 1979, 44, 1438. (b) Kabalka, G. W.; Daley, R. F.
J. Am. Chem. Soc. 1973, 95, 4428.
1H NMR (250 MHz) d 7.37±7.20 (m, 5H), 4.58±4.34 (m,
2H), 3.32±3.19 (m, 1H), 3.01±2.60 (m, 2H), 2.30±1.97 (m,
2H). 13C NMR (62.5 MHz) d 170.6, 142.8, 129.0, 127.3,
126.4, 68.6, 37.5, 37.4, 30.3. Anal. Calcd for C11H12O2: C,
74.98; H, 6.86. Found: C, 74.69; H, 7.04.
3. (a) Jacob, P.; Brown, H. C. J. Am. Chem. Soc. 1976, 98, 7832.
(b) Sinclair, J. A.; Molander, G. A.; Brown, H. C. J. Am.
Chem. Soc. 1977, 99, 954. (c) Molander, G. A.; Brown,
H. C. J. Org. Chem. 1977, 42, 3106.
4.1.23. 3-Phenylmethyltetrahydrofuran-2-one (5ha). IR
(neat) 2915, 1769, 1497, 1454, 1374, 1148, 1023, 957,
4. Ashby, E. C.; Heinsohn, G. J. Org. Chem. 1974, 39, 3297.
5. (a) Luche, J.; Petrier, C.; Lansard, J.; Greene, A. E. J. Org.
Chem. 1983, 48, 3837. (b) Greene, A. E.; Lansard, J.; Luche,
J.; Petrier, C. J. Org. Chem. 1984, 49, 931. (c) Petrier, C.;
Luche, J.; Dupuy, C. Tetrahedron Lett. 1984, 25, 3463.
(d) Soai, K.; Hayasaka, T.; Ugajin, S. J. Chem. Soc., Chem.
Commun. 1989, 516.
751, 702 cm21 1H NMR (250 MHz) d 7.35±7.19 (m,
.
5H), 4.26±4.08 (m, 2H), 2.88±2.71 (m, 2H), 2.28±2.17
(m, 1H), 2.07±1.91 (m, 2H). 13C NMR (62.5 MHz) d
178.7, 138.4, 128.9, 128.7, 126.7, 66.5, 41.1, 36.1, 28.0.
Anal. Calcd for C11H12O2: C, 74.98; H, 6.86. Found: C,
74.80; H, 6.91.
6. Schwarts, J.; Loots, M. J.; Kosugi, H. J. Am. Chem. Soc. 1980,
102, 1333.
4.1.24. 2-Methyl-3-phenylpropanal (7aa).8 IR (neat) 3028,
2970, 2931, 2873, 2813, 2714, 1725, 1496, 1454, 1374,
7. Cacchi, S.; Misiti, D.; Palmieri, G. Tetrahedron 1981, 37,
2941.
1
1164, 927, 742, 701 cm21. H NMR (250 MHz) d 9.77 (d,
8. Cho, C. S.; Motofusa, S.; Ohe, K.; Uemura, S. Bull. Chem.
Soc. Jpn. 1996, 69, 2341.
Jˆ1.5 Hz, 1H), 7.31±7.10 (m, 5H), 3.09 (dd, Jˆ13.6,
5.8 Hz, 1H), 2.69±2.65 (m, 1H), 2.60 (dd, Jˆ13.6, 8.3 Hz,
1H), 1.08 (d, Jˆ6.9 Hz, 3H). 13C NMR (62.5 MHz) d 204.4,
138.9, 129.1, 128.6, 126.5, 48.1, 36.7, 13.3.
9. Ohe, T.; Wakita, T.; Motofusa, S.; Cho, C. S.; Ohe, K.;
Uemura, S. Bull. Chem. Soc. Jpn. 2000, 73, 2149.
10. (a) Sakai, M.; Hayashi, H.; Miyaura, N. Organometallics
1997, 16, 4229. (b) Takaya, Y.; Ogasawara, M.; Hayashi,
T.; Sakai, M.; Miyaura, N. J. Am. Chem. Soc. 1998, 120,
5579. (c) Sakuma, S.; Sakai, M.; Itooka, R.; Miyaura, N.
J. Org. Chem. 2000, 65, 5951.
4.1.25. 3-Phenylbutanal (7ba).8 IR (neat) 2960, 2720,
.
1725, 1601, 1498, 1455, 749, 680 cm21 1H NMR
(250 MHz) d 9.70 (dd, Jˆ2.2, 1.7 Hz, 1H), 7.33±7.19 (m,
5H), 3.36 (ddq, Jˆ7.7, 7.0, 6.8 Hz, 1H), 2.75 (ddd, Jˆ16.6,
6.8, 1.7 Hz, 1H), 2.65 (ddd, Jˆ16.6, 7.7, 2.2 Hz, 1H), 1.32
(d, Jˆ7.0 Hz, 3H). 13C NMR (62.5 MHz) d 201.9, 145.4,
128.7, 126.8, 126.5, 51.7, 34.3, 22.2.
11. Oi, S.; Moro, M.; Inoue, Y. Chem. Commun. 1997, 1621.
12. Oi, S.; Moro, M.; Fukuhara, H.; Kawanishi, T.; Inoue, Y.
Tetrahedron Lett. 1999, 40, 9259.
13. Preliminary communication: (a) Oi, S.; Moro, M.; Ono, S.;
Inoue, Y. Chem. Lett. 1998, 83. Rhodium-catalyzed conjugate
addition of organotin compounds to a,b-unsaturated carbonyl
compounds in air and water was also reported recently:
(b) Venkatraman, S.; Meng, Y.; Li, C. J. Tetrahedron Lett.
2001, 42, 4459. (c) Huang, T.; Li, C. J. Org. Lett. 2001, 3,
2037. (d) Huang, T.; Meng, Y.; Venkatraman, S.; Wang, D.;
Li, C. J. J. Am. Chem. Soc. 2001, 123, 7451.
4.1.26. 3,3-Diphenylpropanal (7ca).9 IR (neat) 2960, 2750,
.
1730, 1605, 1502, 1459, 759, 705 cm21 1H NMR
(250 MHz) d 9.74 (t, Jˆ1.9 Hz, 1H), 7.63±7.10 (m, 10H),
4.62 (t, Jˆ7.8 Hz, 1H), 3.19 (dd, Jˆ7.8, 1.9 Hz, 2H). 13C
NMR (62.5 MHz) d 200.0, 143.2, 128.7, 127.7, 126.7, 49.4,
45.0.
14. Green, M.; Kuc, T. A.; Taylor, S. H. J. Chem. Soc. (A) 1971,
2334.
Acknowledgements
15. Gilman, H.; Rosenberg, S. D. J. Am. Chem. Soc. 1953, 75,
2507.
This work was partially supported by JSPS Research for the
Future Program.
16. Barluenga, J.; Aguilar, E.; Olano, B.; Fustero, S. J. Org. Chem.
1988, 53, 1741.
17. Crowe, W. E.; Zhang, Z. J. J. Am. Chem. Soc. 1993, 115,
10998.
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