Conjugate additions of α,β-unsaturated ketones with arylzinc species that form in situ from diethylzinc and arylboronic acids

Article abstract of DOI:10.1055/s-2004-822339

Conjugate addition of α,β-unsaturated ketones with arylzinc species that form in situ from diethylzinc and a series of arylboronic acids by boron-zinc exchange reactions were investigated. 1,4-Addition products were formed in yields of 34-93%.

Full text of DOI:10.1055/s-2004-822339

PAPER
1057
Conjugate Additions of a,b-Unsaturated Ketones with Arylzinc Species That
Form in situ from Diethylzinc and Arylboronic Acids
Conjugate
A
ddi
i
tions o
n
f
a
,
b
-Unsaturated
K
D
etones
w
ith
A
rylz
o
inc Speciesng, Yan-Jun Xu, Liu-Zhu Gong,* Ai-Qiao Mi, Yao-Zhong Jiang
Key Laboratory for Asymmetric Synthesis and Chirotechnology of Sichuan Province and Union Laboratory of Asymmetric Synthesis,
Chengdu Institute of Organic Chemistry, Chinese Academy of Sciences, Chengdu, 610041, P. R. China
E-mail: gonglz@cioc.ac.cn
Received 10 December 2003; revised 16 March 2004
Table 1 1,4-Addition to Chalcone 1a by the Combination of Aro-
matic Boronic Acids and Diethylzinc
Abstract: Conjugate addition of a,b-unsaturated ketones with
arylzinc species that form in situ from diethylzinc and a series of
arylboronic acids by boron-zinc exchange reactions were investi-
gated. 1,4-Addition products were formed in yields of 34–93%.
Keywords: conjugate addition, a,b-unsaturated ketone, arylboron-
ic acid, boron-zinc exchange reaction
Entry
ArB(OH)2
Ph (2a)
Product 3, (Ar =)
Ph (3a)
Yield (%)a
Conjugate addition of organometallic reagents to elec-
tron-deficient olefins is one of the most versatile methods
for forming carbon-carbon bonds.1 Due to the importance
of the resulting b-substituted carbonyl compounds in or-
ganic synthesis, many conjugate additions of organome-
tallic reagents, such as those of lithium, magnesium, zinc,
and boron, to enones have been extensively studied.2 Re-
cently, important advances have been made regarding
asymmetric conjugate additions of arylboronic acids and
the corresponding esters, and related reactions with alkyl-
zincs.3 These reactions generally require the use of transi-
tion-metal complexes as catalysts. Since arylzinc species
can be formed by boron-zinc exchange reactions,4,5 we
started a project to prepare b-aryl carbonyl compounds via
the conjugate addition of arylzinc, generated in situ from
arylboronic acids and diethylzinc, to a,b-unsaturated ke-
tones.5
1
2
3
4
5
6
92
4-ClPh (2b)
4-CH3OPh (2c)
4-F-Ph (2d)
2-ClPh (2e)
F3C
4-Cl-Ph (3b)
4-CH3OPh (3c)
4-F-Ph (3d)
2-Cl-Ph (3e)
F3C
78
73
88
34
trace
OH
B
OH
F3C
(2f)
O
F3C
(3f)
Ph (3a)
7
44
Ph
B
O
(2g)
a Isolated yield based on 1a.
We first studied the reaction of chalcone (1a) with the
combination of phenylboronic acid and diethylzinc. The
phenylzinc species was prepared by stirring a mixture of
phenylboronic acid and a 3-fold excess of Et2Zn in tolu-
ene at 60 °C under argon for 12 hours. It was then reacted
with chalcone (1a) at 0 °C to give 3a in 92% yield
(Table 1, entry 1).6 The use of several commercial arylbo-
ronic acids 2a–f and an ester 2g in the 1,4-addition of
chalcone (1a) under the above reaction conditions was
then investigated. The results are summarized in Table 1.
drance by the 2-chlorophenyl group (entry 5). Arylzincs
formed from other arylboronic acids, such as phenylbo-
ronic acid and 4-substituted phenylboronic acids, reacted
well with chalcone (1a) to furnish 1,4-adducts 3a–d in
high yields (entries 1–4). Pinacol phenylboronate (2g, en-
try 7) gave a lower yield than its analogue 2a.
As shown in Table 1, 1,4-additions are highly dependent
on the structures of the arylboronic acids. Boronic acid
with two strongly electron-withdrawing trifluoromethyl
groups was not good for 1,4-addition (entry 6). This is
probably due to an incomplete boron-zinc exchange.5 2-
Chlorophenylboronic acid also gave a low yield of 34%
for 1,4-addition, which might be the result of steric hin-
O
O
Ph
Ph2Zn
Ph
Ph
Ph
O
toluene, Ar, 0 °C
3a
Ph
Ph
Ph
1a
Ph2Zn/Et2Zn = 1/1
toluene, Ar, 0 °C
Ph
3a
Scheme 1 Reactions of 1a with Ph2Zn and Ph2Zn–Et2Zn
SYNTHESIS 2004, No. 7, pp 1057–1061
x
x
.
x
x
.2
0
0
4
Advanced online publication: 14.04.2004
DOI: 10.1055/s-2004-822339; Art ID: F12403SS
© Georg Thieme Verlag Stuttgart · New York

1058
L. Dong et al.
PAPER
Table 2 1,4-Addition of 1b–m with PhB(OH)2–Et2Zn (continued)
Scheme 2 Reactions of 1a with Ph2Zn promoted by a mixture of
MeB(OH)2 and Et2Zn
Entry
7
Ketone (1b–m)
Yield of 4b–m (%)
To understand whether the EtB(OZnEt)2 generated in situ
from diethylzinc and arylboronic acid acts as a catalyst to
promote the 1,4-addition of EtZnAr to a,b-unsaturated ke-
tone, chalcone (1a) was treated with Ph2Zn and an orga-
nozinc species formed in situ from Et2Zn–Ph2Zn.7 No 1,4-
addition adduct 3a was produced in either reaction
(Scheme 1). However, the combination of Et2Zn and phe-
nylboronic acid reacted smoothly with chalcone (1a) to
give 3a in 92% yield (Table 1, entry 1). In addition, reac-
tions of 1a with Ph2Zn in the presence of a mixture of
MeB(OH)2 and Et2Zn proceeded well to give 3a in 77%
yield (Scheme 2). These results demonstrated that
EtB(OZnEt)2 might catalyze the 1,4-addition.
89
O
Ph
(1h)
8
9
85
38
O
Ph
(1i)
O
Ph
O2N
(1j)
Table 2 1,4-Addition of 1b–m with PhB(OH)2–Et2Zn
10
11
12
80
O
H3CO
Ph
(1k)
93
O
Entry
1
Ketone (1b–m)
Yield of 4b–m (%)
(1l)
83
O
trace
O
Ph
(1b)
(1m)
2
3
4
5
6
77
90
85
63
53
O
Ph
1,4-Additions of several unsaturated ketones in the pres-
ence of Et2Zn and phenylboronic acid were examined.
The results are listed in Table 2. Most of the tested ke-
tones underwent 1,4-addition to give the expected product
in good yields, except for ketone 1j and 1m. The 1,4-ad-
dition of 1j produced 4j in only 38% yield (entry 9). Only
trace amount of product was observed with unsaturated
ketone 1m (entry 12), which implied that the unsaturated
ketone with an aliphatic substituted carbonyl group was
less reactive. Compound 1f bearing a 2,6-dichlorophenyl
group showed relatively low yield for 1,4-addition (63%
yield), probably due to its steric bulk (entry 5). Reactions
of a,b-unsaturated ketones containing a nitro group al-
ways gave worse results than those of their structural an-
alogues bearing other electron-withdrawing groups
(entries 6 and 9).
OCH3
(1c)
O
Ph
F
(1d)
O
Ph
Br
(1e)
O
Cl
Ph
Cl
(1f)
O
In summary, conjugated additions of a,b-unsaturated ke-
tones with the arylzinc species formed in situ from dieth-
ylzinc and arylboronic acids were studied. 1,4-Addition
products were formed in yields of 34–93%. The observed
1,4-addition of the a,b-unsaturated ketones is useful since
Ph
NO2
(1g)
Synthesis 2004, No. 7, 1057–1061 © Thieme Stuttgart · New York

PAPER
Conjugate Additions of a,b-Unsaturated Ketones with Arylzinc Species
1059
Anal. Calcd for C22H20O2: C, 83.51; H, 6.37. Found: C, 83.35; H,
6.57.
it does not require transition-metal catalysts for the aryl
transfer reactions.2
3d
NMR spectra were recorded on a Brucker-300 MHz spectrometer.
EI Mass spectra were recorded on a VG-7010E spectrometer. IR
spectra were recorded on NicroLab 200SXV spectrometer. Elemen-
tal analysis was performed on Italy CARCOERBA 1106 apparatus.
All reactions that are air and moisture sensitive were carried out un-
der an anhyd argon atmosphere using standard Schlenk line tech-
niques. Toluene was dried with Na–benzophenone. Petroleum ether
(bp 60–90 °C) and EtOAc for column chromatography were dis-
tilled before use.
Yield: 88%; colorless solid; mp 98.2–99.8 °C.
IR (KBr): 3058, 1671, 1510, 1215, 747, 700, 685 cm–1.
1H NMR (300 MHz, CDCl3): d = 3.71 (d, J = 7.3 Hz, 2 H), 4.80 (t,
J = 7.3 Hz, 1 H), 6.93–6.98 (m, 2 H), 7.19–7.29 (m, 7 H), 7.42–7.47
(m, 2 H), 7.53–7.58 (m, 1 H), 7.92–7.95 (m, 2 H).
13C NMR (75 MHz, CDCl3): d = 44.8, 45.1, 115.1, 115.4, 126.5,
127.7, 128.0, 128.6, 129.2, 129.3, 133.1, 136.9, 144.0, 159.7, 163.0,
197.8.
MS (EI, 70 eV): m/z (%) = 304 [M+], 185 (38), 105 (100).
1,4-Addition to Generate 3a–e and 4b–m; General Procedure
Under an argon atmosphere, a solution of diethylzinc in hexane (1.0
M, 2.25 mL, 2.25 mmol) was added to a solution of PhB(OH)2 (91.3
mg, 0.75 mmol) in anhyd toluene (6 mL) in a flame-dried Schlenk
flask (25 mL). After being stirred at 60 °C for 12 h, the reaction mix-
ture was cooled to 0 °C and a solution of 1a (62.4 mg, 0.3 mmol) in
anhyd toluene (1.5 mL) was added. After stirring at 0 °C for 10 h,
the reaction was quenched with sat. aq NH4Cl (10 mL). The result-
ing mixture was extracted with EtOAc (3 × 10 mL). The combined
organic layers were washed with brine and dried over anhyd
Na2SO4. The solvent was removed under vacuum. The residue was
purified by flash chromatography on silica gel (hexane–EtOAc,
35:1) to give 3a as white crystals (79 mg, 92% yield); mp 94.4–95.8
°C.
Anal. Calcd for C21H17FO: C, 82.87; H, 5.63. Found: C, 82.72; H,
5.73.
3e
Yield: 34%; colorless oil.
IR (neat): 3060, 1687, 1447, 750, 693 cm–1.
1H NMR (300 MHz, CDCl3): d = 3.76 (d, J = 7.3 Hz, 2 H), 5.29 (t,
J = 7.3 Hz, 1 H), 7.12–7.29 (m, 8 H), 7.36–7.39 (m, 1 H), 7.41–7.47
(m, 2 H), 7.52–7.59 (m, 1 H), 7.94–7.99 (m, 2 H).
13C NMR (75 MHz, CDCl3): d = 42.2, 43.9,126.4, 126.8, 127.6,
128.0, 128.0, 128.4, 128.4, 128.5, 129.9, 133.1, 136.8, 141.3, 142.4,
197.3.
MS (EI, 70 eV): m/z (%) = 320 [M+], 105 (100).
IR (KBr): 3026, 1677, 1596, 1494, 1450, 1264, 1213, 750, 702
cm–1.
1H NMR (300 MHz, CDCl3): d = 3.64 (d, J = 7.3 Hz, 2 H), 4.72 (t,
J = 7.3 Hz, 1 H), 7.06–7.11 (m, 5 H), 7.16–7.19 (m, 8 H), 7.32–7.37
(m, 2 H), 7.44–7.46 (m, 1 H), 7.83–7.86 (m, 2 H).
Anal. Calcd for C21H17ClO: C, 78.62; H, 5.34. Found: C, 78.93; H,
5.44.
4b
13C NMR (75 MHz, CDCl3): d = 44.6, 45.8, 126.3, 127.8, 128.0,
Yield: 83%; colorless solid; mp 97.4–99.2 °C.
128.5, 128.5, 133.0, 137.0, 144.1, 197.9.
IR (KBr): 3023, 2962, 1677, 1513, 1450, 1261, 1097, 1079, 1026,
801 cm–1.
MS (EI, 70 eV): m/z (%) = 286 [M+], 167 (36), 105 (100).
1H NMR (300 MHz, CDCl3): d = 2.29 (s, 1 H), 3.72 (d, J = 7.3 Hz,
2 H), 4.77 (t, J = 7.3 Hz, 1 H), 7.07–7.10 (m, 2 H), 7.15–7.26 (m, 3
H), 7.26–7.27 (m, 4 H), 7.42–7.47 (m, 2 H), 7.53–7.55 (m, 1 H),
7.92–7.95 (m, 2 H).
13C NMR (75 MHz, CDCl3): d = 20.9, 44.7, 45.5, 126.2, 127.6,
127.7, 128.0, 128.5, 128.5, 129.2, 133.0, 135.8, 137.0, 141.1, 144.3,
198.0.
3b
Yield: 78%; colorless solid; mp 95.4–96.4 °C.
IR (KBr): 3027, 1679, 1492, 1451, 1260, 1208, 757, 746, 701, 685
cm–1.
1H NMR (300 MHz, CDCl3): d = 3.71 (d, J = 7.0 Hz, 2 H), 4.79 (t,
J = 7.0 Hz, 1 H), 7.19–7.29 (m, 9 H), 7.45–7.56 (m, 3 H), 7.92–7.95
(m, 2 H).
MS (EI, 70 eV): m/z (%) = 300 [M+], 181 (95), 105 (100).
13C NMR (75 MHz, CDCl3): d = 44.5, 45.2, 126.5, 127.7, 128.0,
128.6, 129.1, 132.1, 133.2, 136.8, 142.5, 143.6, 197.6.
Anal. Calcd for C22H20O: C, 87.96; H, 6.71. Found: C, 88.18; H,
6.75.
MS (EI, 70 eV): m/z (%) = 320 [M+], 201 (26), 105 (100).
4e
Anal. Calcd for C21H17ClO: C, 78.62; H, 5.34. Found: C, 78.67; H,
5.41.
Yield: 85%; colorless solid; mp 108.9–109.6 °C.
IR (KBr): 3025, 1678, 1488, 1450, 1259, 1207, 754, 743, 700, 686
cm–1.
3c
1H NMR (300 MHz, CDCl3): d = 3.68 (d, J = 1.0 Hz, 1 H), 3.70 (d,
J = 1.0 Hz, 1 H), 4.74 (t, J = 7.2 Hz, 1 H), 7.11–7.14 (m, 2 H), 7.17–
7.27 (m, 5 H), 7.35–7.45 (m, 4 H), 7.52–7.57 (m, 1 H), 7.89–7.93
(m, 2 H).
13C NMR (75 MHz, CDCl3): d = 44.4, 45.2, 120.1, 126.6, 127.6,
127.9, 128.6, 128.6, 129.5, 131.5, 133.1, 136.8, 143.1, 143.5, 197.5.
Yield: 73%; colorless solid; mp 94.6–95.8 °C.
IR (KBr): 3006, 1675, 1514, 1268, 1213, 1037, 702 cm–1.
1H NMR (300 MHz, CDCl3): d = 3.69 (d, J = 7.3 Hz, 2 H), 3.75 (s,
3 H), 4.76 (t, J = 7.3 Hz, 1 H), 6.79–6.82 (m, 2 H), 7.16–7.19 (m, 3
H), 7.25–7.27 (m, 4 H), 7.41–7.46 (m, 2 H), 7.52–7.54 (m, 1 H),
7.91–7.94 (m, 2 H).
13C NMR (75 MHz, CDCl3): d = 44.8, 45.1, 55.1, 113.9, 126.2,
127.7, 128.0, 128.5,128.5, 128.7, 133.0, 136.2, 137.0, 144.5, 158.0,
198.1.
MS (EI, 70 eV): m/z (%) = 364 [M+], 247 (57), 165 (67), 105 (100),
77 (76).
Anal. Calcd for C21H17BrO: C, 69.05; H, 4.69. Found: C, 69.13; H,
4.48.
MS (EI, 70 eV): m/z (%) = 316 [M+], 197 (100).
Synthesis 2004, No. 7, 1057–1061 © Thieme Stuttgart · New York

1060
4f
L. Dong et al.
PAPER
MS (EI, 70 eV): m/z (%) = 331 [M+], 167 (100).
Yield: 63%; colorless oil.
IR (neat): 3059, 3027, 1691, 1448, 1432, 780, 752, 692 cm–1.
Anal. Calcd for C21H17NO3: C, 76.12; H, 5.17; N, 4.23. Found: C,
76.20; H, 5.30; N, 4.32.
1H NMR (300 MHz, CDCl3): d = 3.86 (q, J = 17.6 Hz, 1 H), 4.17 (q,
J = 17.6 Hz, 1 H), 5.85 (t, J = 6.8 Hz, 1 H), 7.05–7.29 (m, 8 H),
7.42–7.7.48 (m, 2 H), 7.56–7.66 (m, 1 H), 7.99–8.02 (m, 2 H).
4k
Yield: 80%; colorless solid; mp 71.2–72.8 °C.
IR (neat): 3059, 3026, 1685, 1596, 1593, 1490, 1451, 1429, 1263,
700 cm–1.
1H NMR (300 MHz, CDCl3): d = 3.61 (d, J = 7.3 Hz, 2 H), 3.70 (s,
3 H), 4.70 (t, J = 7.3 Hz, 1 H), 6.99–7.00 (m, 1 H), 7.03–7.11 (m, 2
H), 7.13–7.16 (m, 8 H), 7.19–7.26 (m, 1 H), 7.33–7.35 (m, 1 H),
7.41–7.45 (m, 1 H).
13C NMR (75 MHz, CDCl3): d = 40.5, 40.5, 126.1, 127.2, 127.8,
128.1, 128.3, 128.6, 133.1, 139.4, 140.7, 197.8.
MS (EI, 70 eV): m/z (%) = 354 [M+], 105 (100), 77 (51).
Anal. Calcd for C21H16Cl2O: C, 71.00; H, 4.54. Found: C, 71.02; H,
4.72.
13C NMR (75 MHz, CDCl3): d = 44.7, 45.9, 55.3, 112.2, 119.6,
4g
120.6, 126.3, 127.8, 128.5, 129.5, 138.3, 144.0, 159.7, 197.7.
Yield: 53%; yellow oil.
IR (neat): 3060, 3028, 1686, 1597, 1517, 1345, 747, 700 cm–1.
MS (EI, 70 eV): m/z (%) = 316 [M+], 167 (50), 135 (100).
Anal. Calcd for C22H20O2: C, 83.51; H, 6.37. Found: C, 83.83; H,
6.21.
1H NMR (300 MHz, CDCl3): d = 3.77 (t, J = 6.0 Hz, 2 H), 4.91 (t,
J = 7.3 Hz, 1 H), 7.22–7.32 (m, 5 H), 7.42–7.48 (m, 4 H), 7.55–7.60
(m, 1 H), 7.93–7.96 (m, 2 H), 8.10–8.14 (m, 2 H).
13C NMR (75 MHz, CDCl3): d = 44.1, 45.7, 123.8, 127.0, 127.7,
128.0, 128.7, 128.9, 129.1, 133.4, 136.5, 142.5, 146.4, 151.7, 197.1.
4l
Yield: 93%; colorless oil.
IR (neat): 3083, 3059, 2958, 2928, 2870, 1684, 1596, 1493, 1447,
749, 700, 689 cm–1.
MS (EI, 70 eV): m/z (%) = 331 [M+], 105 (100).
1H NMR (300 MHz, CDCl3): d = 0.80 (d, J = 6.6 Hz, 3 H), 0.99 (d,
J = 6.6 Hz, 3 H), 1.91 (m, 1 H), 3.15 (q, J = 6.9 Hz, 1 H), 3.36 (d,
J = 6.7 Hz, 2 H), 7.16–7.29 (m, 5 H), 7.39–7.44 (m, 2 H), 7.50–7.52
(m, 1 H), 7.88–7.90 (m, 2 H).
13C NMR (75 MHz, CDCl3): d = 20.4, 21.0, 33.3, 42.6, 47.9, 126.1,
128.0, 128.1, 128.4, 128.5, 132.8, 137.4, 143.6, 199.5.
Anal. Calcd for C21H17NO3: C, 76.12; H, 5.17; N, 4.23. Found: C,
76.19; H, 5.45; N, 4.36.
4h
Yield: 89%; colorless solid; mp 124.1–125.5 °C.
IR (KBr): 3056, 1677, 1596, 1448, 1200, 779, 759, 699 cm–1.
1H NMR (300 MHz, CDCl3): d = 3.82 (q, J = 7.3 Hz, 2 H), 5.63 (t,
J = 7.3 Hz, 1 H), 7.13–7.58 (m, 12 H), 7.70–7.73 (m, 1 H), 7.76–
7.83 (m, 1 H), 7.91–7.94 (m, 2 H), 8.15–8.18 (m, 1 H).
MS (EI, 70 eV): m/z (%) = 252 [M+], 132 (74), 105 (100).
Acknowledgment
13C NMR (75 MHz, CDCl3): d = 41.3, 45.0, 123.7, 124.3, 125.1,
125.4, 126.1, 126.3, 127.2, 127.9, 128.0, 128.4, 128.5, 128.7, 131.5,
133.0, 134.0, 136.9, 139.6, 143.8, 197.8.
We are grateful to the National Natural Science Foundation of Chi-
na for the financial support (projects 20325211 and 203900505).
MS (EI, 70 eV): m/z (%) = 336 [M+], 217 (100), 105 (87).
Anal. Calcd for C25H20O: C, 89.25; H, 5.99. Found: C, 89.34; H,
6.00.
References
(1) (a) Pertter, P. Conjugate Addition Reactions in Organic
Synthesis; Pergamon Press: Oxford, 1992. (b) Rossiter, B.
E.; Swingle, N. M. Chem. Rev. 1992, 92, 771.
4i
Yield: 85%; colorless solid; mp 81.1–81.8 °C.
(2) (a) For leading references on organolithium: Cooke, M. P. J.
Org. Chem. 1984, 49, 1144. (b) Organomagnesium: Modi,
S. P.; Gardner, J. O.; Milowsky, A.; Wierzba, M.; Forgione,
L.; Mazur, P.; Solo, A. J.; Duax, W. L.; Galdecki, Z.;
Grochulski, P.; Wawrzak, Z. J. Org. Chem. 1989, 54, 2317.
(c) Also see: Maruoka, K.; Imoto, H.; Saito, S.; Yamamoto,
H. J. Am. Chem. Soc. 1994, 116, 4131. (d) Organozinc:
Knochel, P.; Singer, R. D. Chem. Rev. 1993, 93, 2117.
(e) Also see: Hanson, M. V.; Rieke, R. D. J. Am. Chem. Soc.
1995, 117, 10775. (f) Organoboronic acid and esters: Sakai,
M.; Hayasagi, H.; Miyaura, N. Organometallics 1997, 16,
4229. (g) Also see: Nishikata, T.; Yamamoto, Y.; Miyaura,
N. Angew. Chem. Int. Ed. 2003, 42, 2768.
IR(KBr): 3059, 3027, 1681, 1395, 1507, 1493, 789, 778, 700 cm–1.
1H NMR (300 MHz, CDCl3): d = 3.86 (d, J = 7.5 Hz, 2 H), 4.73 (t,
J = 7.5 Hz, 1 H), 7.01–7.33 (m, 10 H), 7.47–7.51 (m, 3 H), 7.76–
8.23 (m, 4 H).
13C NMR (75 MHz, CDCl3): d = 46.5, 48.3, 124.2, 125.6, 126.3,
126.4, 126.7, 127.6, 127.8, 128.2, 128.5, 129.9, 132.3, 133.8, 136.5,
143.8, 202.5.
MS (EI, 70 eV): m/z (%) = 336 [M+], 155 (100).
Anal. Calcd for C25H20O: C, 89.25; H, 5.99. Found: C, 89.05; H,
5.99.
(3) For reviews of asymmetric catalysis: (a) Tomioka, K.;
Nagaoka, Y. In Comprehensive Asymmetric Catalysis;
Jacobsen, E. N.; Pfaltz, A.; Yamamoto, H., Eds.; Springer:
Berlin, 1999. (b) Kanai, M.; Shibasaki, M. In Catalytic
Asymmetric Synthesis; Ojima, I., Ed.; Wiley: New York,
2000, 569–592. (c) Hayashi, T.; Yamasaki, K. Chem. Rev.
2003, 103, 2829.
4j
Yield: 38%; colorless solid; mp 137.9–139.5 °C.
IR (KBr): 3109, 3022, 1693, 1599, 1516, 1345, 750, 700 cm–1.
1H NMR (300 MHz, CDCl3): d = 3.76 (d, J = 7.3 Hz, 2 H), 4.77 (t,
J = 7.3 Hz, 1 H), 7.18–7.29 (m, 10 H), 8.03–8.06 (m, 2 H), 8.26–
8.29 (m, 2 H).
13C NMR (75 MHz, CDCl3): d = 45.2, 45.9,123.8, 126.6, 127.6,
128.4, 129.0, 141.3, 143.4, 196.7.
Synthesis 2004, No. 7, 1057–1061 © Thieme Stuttgart · New York

PAPER
Conjugate Additions of a,b-Unsaturated Ketones with Arylzinc Species
1061
(4) (a) Srebnik, M. Tetrahedron Lett. 1991, 32, 2449.
(5) Bolm, C.; Rudolph, J. J. Am. Chem. Soc. 2002, 124, 14850.
(6) Decreasing the amount of Et2Zn led to an incomplete
reaction.
(7) (a) Bolm, C.; Kesselgruber, M.; Hermanns, N.; Hildebrand,
J. P.; Raabe, G. Angew. Chem. Int. Ed. 2001, 40, 1488.
(b) Bolm, C.; Hermanns, N.; Hildebrand, J. P.; Muñiz, K.
Angew. Chem. Int. Ed. 2000, 39, 3465.
(b) Oppolzer, W.; Radinov, R. N. J. Am. Chem. Soc. 1993,
115, 1593. (c) Langer, F.; Schwink, L.; Devasagayaraj, A.;
Chavant, P.-Y.; Knochel, P. J. Org. Chem. 1996, 61, 8229.
(d) Boudier, A.; Bromm, L. O.; Lotz, M.; Knochel, P.
Angew. Chem. Int. Ed. 2000, 39, 4414. (e) Dahmen, S.;
Bräse, S. Org. Lett. 2001, 3, 4119.
Synthesis 2004, No. 7, 1057–1061 © Thieme Stuttgart · New York