Reaction of N-tosylated imines with α,β-acetylenic ketones via organozinc species

Article abstract of DOI:10.1080/00397910903219294

A new procedure for stereoselective synthesis of trisubstituted alkenes by an one-pot, three-component reaction of N-tosylated imines with,-acetylenic ketones and organozinc species CF₃COOZnEt was described. This reaction system provides-branched Morita-Baylis-Hillman adducts with excellent yields in absence of any catalyst. Copyright

Full text of DOI:10.1080/00397910903219294

Synthetic Communications1, 40: 1944–1953, 2010
Copyright # Taylor & Francis Group, LLC
ISSN: 0039-7911 print=1532-2432 online
DOI: 10.1080/00397910903219294
REACTION OF N-TOSYLATED IMINES WITH
a,b-ACETYLENIC KETONES VIA
ORGANOZINC SPECIES
Yong-Kang Liu,1 Quan-Ping Wu,2 Qing-Xiang Guo,1
and Song Xue2
1Department of Chemistry, University of Science and Technology of China,
Hefei, China
2Department of Applied Chemistry, Tianjin University of Technology,
Tianjin, China
A new procedure for stereoselective synthesis of trisubstituted alkenes by an one-pot,
three-component reaction of N-tosylated imines with a,b-acetylenic ketones and organozinc
species CF3COOZnEt was described. This reaction system provides b-branched Morita–
Baylis–Hillman adducts with excellent yields in absence of any catalyst.
Keywords: a,b-Acetylenic ketones; CF3COOZnEt; N-tosylated imines; trisubstituted alkenes
INTRODUCTION
Among the reactions in which C–C bonds are formed, the Morita–Baylis–
Hillman reaction (MBH) is one of the most economical and important carbon–
carbon bond-forming reactions.[1,2] The MBH adducts, which are allylic alcohol or
allylic amine derivatives, play an important role in bringing latitude to organic syn-
thesis and in the construction of molecular assemblies as useful intermediates.[3]
However, this reaction suffers from slow reaction rates, which limit the scope of sub-
strates.[4] Many methods to accelerate the reaction rate, such as change in catalyst,
irradiation with microwaves, reaction under high pressure, and reaction in ionic
liquids, have been developed.[5–7]
Organozinc reagents have been widely used in the conjugate addition to various
reagents.[8–10] Nevertheless, the reaction of organozinc reagents with a,b-acetylenic
ketones has not been reported thus far.[11,12] Recently, we reported a new procedure
for synthesis of b-branched MBH adducts by the reaction of a,b-acetylenic ketones
with organozinc species and aldehydes.[13] In continuation of our interest in exploring
the reactivity and behavior of the organozinc species CF3CO2ZnR with electrophiles,
we wanted to examine reactions of N-tosylated imines with a,b-acetylenic ketones and
the organozinc species CF3COOZnEt. Fortunately, CF3COOZnEt can react with
Received February 21, 2008.
Address correspondence to Song Xue, Department of Applied Chemistry, Tianjin University of
Technology, Tianjin 300191, China. E-mail: xuesong@ustc.edu.cn
1944

REACTION OF N-TOSYLATED IMINES
1945
Scheme 1. The reaction of N-tosylated imines with a,b-acetylenic ketones in the presence of
CF3COOZnEt.
terminal a,b-acetylenic ketones and N-tosylated imines with good yields in absence of
any catalyst (Scheme 1). Here we report these results.
RESULTS AND DISCUSSION
Initially, we carried out reactions using different quantities of reagents in
CH2Cl2. The best results were obtained with a 1.0:1.5:1.5 ratio of N-tosylated imines,
a,b-acetylenic ketones, and CF3COOZnEt. Treatment of the in situ–generated
CF3CO2ZnEt[13,14] with 1-phenylprop-2-yn-1-one and N-benzylidene-4-methylben-
zenesulfonamide in CH2Cl2 at room temperature for 10 h generated b-substituted
Baylis–Hillman adducts 3a in 94% isolated yield (entry 1, Table 1). The reaction
was performed in diethyl ether and tetrahydrofuran (THF) and gave the desired
adducts 3a in 5% and 21% respectively. Thus, CH2Cl2 was the solvent of choice.
With the optimal reaction conditions in hand, a variety of a,b-acetylenic
ketones were then allowed to react with N-tosylated imines and CF3CO2ZnEt. These
results are presented in Table 1. Both aliphatic and aromatic acetylenic ketones
could be employed. The reaction of aromatic acetylenic ketones with N-tosylated
imines proceeded smoothly and provided the corresponding products in good yields.
The substituents on the benzene ring of aromatic acetylenic ketones seem to have no
obvious effect on the yields. However, it should be noted that 1-(4-nitrophenyl)prop-
2-yn-1-one provided the desired product 3l in a moderate yield (52%) at room tem-
perature (Table 1, entry 14), which was due to the high reactivity of the acetylenic
ketone, leading to formation of the direct self-condensation product. [The 1,4-
conjugate addition of CF3COOZnEt to a,b-acetylenic ketone generates an
allenolate 4 (Scheme 2), which reacts with secondary a,b-acetylenic ketone to form
a small amount of self-condensation products as by-products.] When the reaction
temperature decreased to 0 ꢀC, the yield of 3 l increased to 64%. Aliphatic a,b-
acetylenic ketones, instead of aromatic a,b-acetylenic ketones, can also react with
N-tosylated imines to provide the b-branched MBH adducts in moderate yields.
The poor yields obtained might be ascribed to the lesser reactivity of aliphatic acet-
ylenic ketones than that of aromatic acetylenic ketones. On the other hand, various
N-tosylated imines were submitted to this reaction, and the corresponding products
were obtained in good yields. The substituents on the benzene ring of N-tosylated
imines seem to have no obvious effect on the yields. The stereochemistry of the
b-branched Baylis–Hillman adducts was determined to be Z configuration for all
cases in our reaction system as revealed by 1H NMR analyses of the crude products.
1
The E-isomer of the product was not observed from the H and 13C NMR spectra.

1946
Y.-K. LIU ET AL.
Table 1. Reactions of N-tosylated imines with a,b-acetylenic ketones and CF3COOZnEt
Entry
R1
R2
Product
Yielda (%)
1
2
C6H5
C6H5
C6H5
C6H5
C6H5
C6H5
3a
3a
3a
3b
3c
3d
3e
3f
94
5b
c
3
21
4
C6H5
C6H5
4-MeC6H4
4-MeOC6H4
4-ClC6H4
CH3
91
90
5
6
C6H5
C6H5
86
75
7
8
4-MeC6H4
4-MeC6H4
4-MeC6H4
4-MeC6H4
4-MeC6H4
4-MeC6H4
4-MeC6H4
4-MeC6H4
4-MeC6H4
4-MeOC6H4
4-MeOC6H4
4-MeOC6H4
4-MeOC6H4
4-ClC6H4
4-ClC6H4
2-ClC6H4
2-ClC6H4
C6H5
85
84
9
4-MeC6H4
4-MeOC6H4
4-FC6H4
4-ClC6H4
4-BrC6H4
4-NO2C6H4
CH3
3g
3h
3i
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
81
93
3j
89
85
52 (64)d
73
78
3k
3l
3m
3n
3o
3p
3q
3r
3s
3t
C6H13
C6H5
90
88
4-MeOC6H4
4-BrC6H4
CH3
86
74
4-MeOC6H4
4-FC6H4
4-MeC6H4
4-BrC6H4
92
95
3u
3v
88
87
aYields after purification by column chromatography.
bPerformed in Et2O.
cPerformed in THF.
dPerformed at 0 ꢀC.
Scheme 2. Plausible mechanism for the reaction.

REACTION OF N-TOSYLATED IMINES
1947
Based on the works of Kitamura et al.[15] and Taniguchi et al.,[16] a plausible
mechanism of the reaction was proposed, as shown in Scheme 2. The first step of
the reaction is the 1,4-conjugate addition of the organozinc species CF3COOZnEt
to a,b-acetylenic ketone to form an active allenolate intermediate 4. The N-tosylated
imine coordinates with the zinc atom, which serves to orient N-tosylated imines for
attack on allenolate. Therefore, the steric interaction between N-tosylated imine R1
group and Et at the b-position of the allenolate dominates the stereochemistry of this
reaction. The N-tosylated imine attacks the allenolate from the less hindered side of
the allenolate 4 to provide Z-isomer as the product.
In conclusion, an efficient method for the synthesis of functionalized trisubsti-
tuted olefins has been developed. The reactions of N-tosylated imines with a,b-
acetylenic ketones and organozinc species CF3CO2ZnEt proceed smoothly in the
absence of any catalyst. The procedure can be subjected to aliphatic and aromatic
a,b-acetylenic ketones, which affords b-branched MBH adducts in moderate to
excellent yields.
EXPERIMENTAL
General Procedure: Reaction of N-Tosylated Imines with a,b-
Acetylenic Ketones and CF3CO2ZnEt
CF3COOH (58 mL, 0.75 mmol) slowly was added dropwise via syringe to a sol-
ution of Et2Zn (80 mL, 0.75 mmol) in 2 mL CH2Cl2 at 0 ꢀC under N2. After stirring
for 30 min at 0 ꢀC, N-tosylated imines (0.5 mmol) were added, and then acetylenic
ketone (0.75 mmol) was added. The mixture was stirred for 10 h at room temperature
until thin-layer chromatography (TLC) indicated complete consumption of the start-
ing N-tosylated imines. The reaction was quenched by saturated aqueous NH4Cl and
extracted with Et2O (3 ꢁ 10 mL). The combined organic extracts were washed with
brine, dried over MgSO4, and concentrated under reduced pressure to an oily resi-
due. The desired product was isolated by silica-gel chromatography with petroleum
ether=EtOAc (5:1–3:1).
Spectral Data
Compound 3a. 1H NMR (300 MHz, CDCl3) d, ppm: 0.80 (t, J ¼ 7.5 Hz, 3H),
1.68 ꢂ 1.80 (m, 2H), 2.42 (s, 3H), 5.26 (d, J ¼ 7.8 Hz, 1H), 5.82 (t, J ¼ 7.5 Hz, 1H),
6.08 (d, J ¼ 7.8 Hz, 1H), 7.17 ꢂ 7.24 (m, 7H), 7.31 ꢂ 7.40 (m, 2H), 7.53 (t, J ¼ 7.5 Hz,
1H), 7.61 (d, J ¼ 6.9 Hz, 2H), 7.73 (d, J ¼ 8.4 Hz, 2H). 13C NMR (75 MHz, CDCl3) d,
ppm: 13.3, 21.5, 23.4, 62.1, 126.9, 127.3, 127.7, 128.56, 128.58, 129.1, 129.5, 133.5,
136.8, 137.6, 137.9, 138.6, 138.8, 143.2, 199.1. IR (neat): 3284, 1648, 1596, 1449,
1330, 1238, 1161 cmꢂ1. HRMS (EI) calcd. for C18H18NO (MꢂTsþ): 264.1388; found
264.1392.
Compound 3b. 1H NMR (300 MHz, CDCl3) d, ppm: 0.72 (t, J ¼ 7.5 Hz, 3H),
1.64 (m, 2H), 2.33 (s, 3H), 2.34 (s, 3H), 5.19 (d, J ¼ 7.8 Hz, 1H), 5.69 (t, J ¼ 7.5 Hz,
1H), 6.14 (d, J ¼ 7.8 Hz, 1H), 7.12 ꢂ 7.17 (m, 9H), 7.46 (d, J ¼ 8.1 Hz, 2H), 7.66 (d,
J ¼ 8.1 Hz, 2H). 13C NMR (75 MHz, CDCl3) d, ppm: 13.2, 21.4, 21.7, 23.3, 62.0,
126.9, 127.2, 127.5, 128.4, 129.2, 129.3, 129.4, 134.9, 136.8, 137.86, 137.92, 138.8,

1948
Y.-K. LIU ET AL.
143.0, 144.5, 198.7. IR (neat): 3285, 3028, 1622, 1604, 1414, 1341, 1162, 1094 cmꢂ1
HRMS (EI) calcd. for C19H20NO (MꢂTsþ): 278.1545; found 278.1541.
.
Compound 3c. 1H NMR (300 MHz, CDCl3) d, ppm: 0.80 (t, J ¼ 7.5 Hz, 3H),
1.70 (m, 2H), 2.41 (s, 3H), 3.75 (s, 3H), 5.21 (d, J ¼ 7.5 Hz, 1H), 5.82 (t, J ¼ 7.5 Hz,
1H), 6.03 (d, J ¼ 7.5 Hz, 1H), 6.74 (d, J ¼ 8.7 Hz, 2H), 7.12 (d, J ¼ 8.7 Hz, 2H), 7.22
(d, J ¼ 8.1 Hz, 2H), 7.38 (t, J ¼ 7.5 Hz, 2H), 7.53 (d, J ¼ 7.5 Hz, 1H), 7.65 (d,
J ¼ 7.5 Hz, 2H), 7.71 (d, J ¼ 8.1 Hz, 2H). 13C NMR (75 MHz, CDCl3) d, ppm:
13.3, 21.5, 23.3, 55.2, 61.2, 113.9, 127.2, 128.2, 128.5, 129.1, 129.4, 130.9, 133.4,
137.1, 137.5, 137.8, 138.0, 143.1, 159.0, 199.1. IR (neat): 3283, 1710, 1647, 1596,
1571, 1508, 1455, 1421, 1323, 1258, 1160 cmꢂ1. HRMS (EI) calcd. for C19H20NO2
(MꢂTsþ): 294.1494; found 294.1493.
Compound 3d. 1H NMR (300 MHz, CDCl3) d, ppm: 0.73 (t, J ¼ 7.5 Hz, 3H),
1.55 ꢂ 1.70 (m, 2H), 2.34 (s, 3H), 5.22 (d, J ¼ 8.4 Hz, 1H), 5.76 (t, J ¼ 7.5 Hz, 1H),
6.13 (d, J ¼ 8.4 Hz, 1H), 7.09 ꢂ 7.15 (m, 7H), 7.25 ꢂ 7.29 (m, 2H), 7.51 (d, J ¼ 8.7 Hz,
2H), 7.63 (d, J ¼ 8.1 Hz, 2H). 13C NMR (75 MHz, CDCl3) d, ppm: 13.3, 21.5, 23.4,
61.7, 126.9, 127.2, 127.7, 128.6, 128.9, 129.5, 130.5, 135.8, 136.8, 137.8, 138.3, 138.6,
140.0, 143.2, 197.8. IR (KBr): 3292, 1625, 1588, 1449, 1402, 1340, 1231, 1161 cmꢂ1
HRMS (EI) calcd. for C18H17NOCl (MꢂTsþ): 298.0999; found 298.0994.
.
Compound 3e. 1H NMR (300 MHz, CDCl3) d, ppm: 0.94 (t, J ¼ 7.5 Hz, 3H),
2.07 (s, 3H), 2.22 (m, 2H), 2.39 (s, 3H), 5.15 (d, J ¼ 8.9 Hz, 1H), 5.65 (d, J ¼ 8.9 Hz,
1H), 5.73 (t, J ¼ 7.5 Hz, 1H), 7.28 ꢂ 7.10 (m, 7H), 7.65 (d, J ¼ 8.1 Hz, 2H).13C NMR
(75 MHz, CDCl3) d, ppm: 13.7, 21.5, 23.1, 31.9, 61.6, 126.7, 127.3, 127.6, 128.6,
129.5, 138.1, 138.8, 139.1, 142.0, 143.3, 203.2. IR (KBr): 2963, 1656, 1494, 1418,
1330, 1262, 1160 cmꢂ1. HRMS (EI) calcd. for C13H16NO (MꢂTsþ): 202.1232; found
202.1235.
Compound 3f. 1H NMR (300 MHz, CDCl3) d, ppm: 0.65 (t, J ¼ 7.5 Hz, 3H),
1.58 (m, 2H), 2.13 (s, 3H), 2.27 (s, 3H), 5.09 (d, J ¼ 7.5 Hz, 1H), 5.90 (t, J ¼ 7.5 Hz,
1H), 6.33 (d, J ¼ 7.5 Hz, 1H), 7.03 (d, J ¼ 8.1 Hz, 2H), 7.09 (d, J ¼ 8.1 Hz, 2H), 7.20
(d, J ¼ 8.1 Hz, 2H), 7.38 (t, J ¼ 7.5 Hz, 2H), 7.53 (t, J ¼ 7.5 Hz, 1H),7.66 (d,
J ¼ 7.5 Hz, 2H), 7.70 (d, J ¼ 8.1 Hz, 2H). 13C NMR (75 MHz, CDCl3) d, ppm:
13.3, 21.1, 21.5, 23.4, 61.7, 126.9, 127.3, 128.6, 129.2, 129.3, 129.5, 133.5, 135.8,
137.0, 137.4, 137.6, 137.9, 138.4, 143.1, 199.1. IR (KBr): 3293, 1623, 1595, 1509,
1425, 1382, 1332, 1156 cmꢂ1. HRMS (EI) calcd. for C19H20NO (MꢂTsþ):
278.1545; found 278.1543.
Compound 3g. 1H NMR (300 MHz, CDCl3) d, ppm: 0.72 (t, J ¼ 7.5 Hz, 3H),
1.64 (m, 2H), 2.21 (s, 3H), 2.33 (s, 3H), 2.34 (s, 3H), 5.66 (d, J ¼ 7.8 Hz, 1H), 5.70 (t,
J ¼ 7.5 Hz, 1H), 6.12 (d, J ¼ 7.8 Hz, 1H), 6.95 (d, J ¼ 7.8 Hz, 2H), 7.07 ꢂ 7.12 (m,
6H), 7.50 (d, J ¼ 8.1 Hz, 2H), 7.65 (d, J ¼ 8.1 Hz, 2H). 13C NMR (75 MHz, CDCl3)
d, ppm: 13.2, 21.0, 21.4, 21.7, 23.2, 61.7, 126.8, 127.2, 129.1, 129.16, 129.22, 129.3,
135.0, 135.8, 137.0, 137.1, 137.7, 137.9, 143.0, 144.4, 198.6. IR (KBr): 3268, 1626,
1602, 1513, 1427, 1384, 1341, 1262, 1161 cmꢂ1. HRMS (EI) calcd. for C20H22NO
(MꢂTsþ): 292.1701; found 292.1694.
Compound 3h. 1H NMR (300 MHz, CDCl3) d, ppm: 0.80 (t, J ¼ 7.5 Hz, 3H),
1.63 ꢂ 1.82 (m, 2H), 2.28 (s, 3H), 2.42 (s, 3H), 3.88 (s, 3H), 5.17 (d, J ¼ 7.5 Hz, 1H),

REACTION OF N-TOSYLATED IMINES
1949
5.72 (t, J ¼ 7.5 Hz, 1H), 6.10 (d, J ¼ 7.5 Hz, 1H), 6.85 (d, J ¼ 8.7 Hz, 2H), 7.01 (d,
J ¼ 8.1 Hz, 2H), 7.11 (d, J ¼ 8.1 Hz, 2H), 7.22 (d, J ¼ 8.1 Hz, 2H), 7.64 (d, J ¼ 8.7 Hz,
2H), 7.72 (d, J ¼ 8.1 Hz, 2H). 13C NMR (75 MHz, CDCl3) d, ppm: 13.3, 21.0, 21.5,
23.2, 55.5, 61.8, 113.8, 126.8, 127.3, 129.1, 129.4, 130.4, 131.7, 135.8, 137.0, 137.1,
137.2, 137.9, 143.0, 164.0, 197.5. IR (neat): 3428, 1956, 1682, 1493, 1453, 1372,
1212 cmꢂ1. HRMS (EI) calcd. for C20H22NO2 (MꢂTsþ): 308.1651; found 308.1653.
Compound 3i. 1H NMR (300 MHz, CDCl3) d, ppm: 0.77 (t, J ¼ 7.5 Hz, 3H),
1.60 ꢂ 1.75 (m, 2H), 2.23 (s, 3H), 2.37 (s, 3H), 5.13 (d, J ¼ 7.5 Hz, 1H), 5.76 (d,
J ¼ 7.5 Hz, 2H), 5.79 (t, J ¼ 7.8 Hz, 2H), 6.95 ꢂ 7.03 (m, 6H), 7.18 (d, J ¼ 8.1 Hz,
2H), 7.61 ꢂ 7.68 (m, 4H). 13C NMR (75 MHz, CDCl3) d, ppm: 13.3, 21.0, 21.5,
23.3, 61.5, 115.6, 115.9, 126.8, 127.3, 129.2, 129.4, 131.8, 132.0, 133.8, 135.6,
137.0, 137.4, 137.8, 143.2, 197.4. IR (neat): 3435, 1683, 1611, 1585, 1512, 1249,
1174 cmꢂ1. HRMS (EI) calcd. for C19H19NOF (MꢂTsþ): 296.1451; found 296.1450.
Compound 3j. 1H NMR (300 MHz, CDCl3) d, ppm: 0.77 (t, J ¼ 7.5 Hz, 3H),
1.58 ꢂ 1.74 (m, 2H), 2.23 (s, 3H), 2.37 (s, 3H), 5.13 (d, J ¼ 7.5 Hz, 1H), 5.77 (d,
J ¼ 7.5 Hz, 1H), 5.80 (t, J ¼ 7.5 Hz, 1H), 6.93 ꢂ 7.04 (m, 4H), 7.18 (d, J ¼ 8.4 Hz,
2H), 7.30 (d, J ¼ 8.7 Hz, 2H), 7.53 (d, J ¼ 8.7 Hz, 2H), 7.65 (d, J ¼ 8.4 Hz, 2H).
13C NMR (75 MHz, CDCl3) d, ppm: 13.3, 21.1, 21.5, 23.4, 61.4, 126.8, 127.3,
128.9, 129.2, 129.3, 129.4, 130.6, 125.6, 136.9, 137.5, 137.8, 138.2, 140.0, 143.2,
197.7. IR (neat): 3298, 1635, 1587, 1509, 1421, 1340, 1231, 1160 cmꢂ1. HRMS (EI)
calcd. for C19H19NOCl (MꢂTsþ): 312.1155; found 312.1154.
Compound 3k. 1H NMR (300 MHz, CDCl3) d, ppm: 0.77 (t, J ¼ 7.5 Hz, 3H),
1.70 (m, 2H), 2.23 (s, 3H), 2.37 (s, 3H), 5.13 (d, J ¼ 7.5 Hz, 1H), 5.78 (t, J ¼ 7.5 Hz,
1H), 5.82 (d, J ¼ 7.5 Hz, 1H), 6.97 ꢂ 7.03 (m, 4H), 7.18 (d, J ¼ 8.1 Hz, 2H), 7.44 ꢂ
7.49 (m, 4H), 7.65 (d, J ¼ 8.1 Hz, 2H). 13C NMR (75 MHz, CDCl3) d, ppm: 13.3,
21.1, 21.5, 23.4, 61.3, 126.8, 127.2, 128.7, 129.3, 129.4, 130.6, 131.9, 135.6, 136.3,
136.9, 137.4, 137.7, 138.2, 143.2, 197.9. IR (neat): 3441, 2923, 1633, 1596, 1505,
1422, 1340, 1227, 1160 cmꢂ1. HRMS (EI) calcd. for C19H19NOBr (MꢂTsþ):
356.0650; found 356.0648.
Compound 3l. 1H NMR (300 MHz, CDCl3) d, ppm: 0.79 (t, J ¼ 7.5 Hz, 3H),
1.66 ꢂ 1.73 (m, 2H), 2.22 (s, 3H), 2.37 (s, 3H), 5.19 (d, J ¼ 7.5 Hz, 1H), 5.74 (t,
J ¼ 7.8 Hz, 1H), 5.97 (d, J ¼ 7.5 Hz, 1H), 6.95 ꢂ 6.99 (m, 4H), 7.18 (d, J ¼ 7.8 Hz,
2H), 7.65 (d, J ¼ 7.8 Hz, 2H), 7.74 (d, J ¼ 8.4 Hz, 2H), 8.17 (d, J ¼ 8.4 Hz, 2H).
13C NMR (75 MHz, CDCl3) d, ppm: 13.3, 21.1, 21.6, 23.6, 61.3, 123.9, 126.8,
127.3, 129.5, 129.6, 130.0, 135.4, 137.0, 137.7, 137.9, 139.6, 142.3, 143.5, 150.5,
197.4. IR (neat): 3234, 2964, 1665, 1560, 1524, 1431, 1345, 1262, 1239, 1158 cmꢂ1
HRMS (EI) calcd. for C19H19N2O3 (MꢂTsþ): 323.1396; found 323.1400.
.
Compound 3m. 1H NMR (300 MHz, CDCl3) d, ppm: 0.94 (t, J ¼ 7.5 Hz,
3H), 2.05 (s, 3H), 2.14 (m, 2H), 2.26 (s, 3H), 2.37 (s, 3H), 5.10 (d, J ¼ 8.9 Hz, 1H),
5.65 (d, J ¼ 8.9 Hz, 1H), 5.73 (t, J ¼ 7.5 Hz, 1H), 6.98 ꢂ 7.01 (m, 4H), 7.19 (d,
J ¼ 8.1 Hz, 2H), 7.63 (d, J ¼ 8.4 Hz, 2H). 13C NMR (75 MHz, CDCl3) d, ppm:
13.7, 21.1, 21.5, 23.1, 31.9, 61.3, 126.6, 127.3, 129.3, 129.5, 136.1, 137.4, 138.1,
138.9, 141.7, 143.2, 203.2. IR (neat): 3240, 2920, 2837, 1655, 1428, 1334,
1164 cmꢂ1. HRMS (EI) calcd. for C14H18NO (MꢂTsþ): 216.1388; found 216.1387.

1950
Y.-K. LIU ET AL.
Compound 3n. 1H NMR (300 MHz, CDCl3) d, ppm: 0.83 (t, J ¼ 7.2 Hz, 3H),
0.91 (t, J ¼ 7.5 Hz, 3H), 1.04 ꢂ 1.22 (m, 6H), 1.25 ꢂ 1.36 (m, 2H), 1.96 ꢂ 2.17 (m,
4H), 2.27 (s, 3H), 2.38 (s, 3H), 5.09 (d, J ¼ 8.7 Hz, 1H), 5.61 (t, J ¼ 7.5 Hz, 1H),
5.72 (d, J ¼ 8.7 Hz, 1H), 6.98 ꢂ 7.02 (m, 4H), 7.19 (d, J ¼ 8.1 Hz, 2H), 7.64 (d,
J ¼ 8.1 Hz, 2H). 13C NMR (75 MHz, CDCl3) d, ppm: 13.8, 14.1, 21.1, 21.5, 22.5,
23.0, 23.6, 28.7, 31.6, 44.1, 61.3, 126.8, 127.3, 129.3, 129.5, 136.0, 137.4, 137.1,
139.4, 139.5, 143.2, 206.8. IR (neat): 3297, 1658, 1512, 1418, 1339, 1161 cmꢂ1
HRMS (EI) calcd. for C19H28NO (MꢂTsþ): 286.2171; found 286.2166.
.
Compound 3o. 1H NMR (300 MHz, CDCl3) d, ppm: 0.80 (t, J ¼ 7.5 Hz, 3H),
1.70 (m, 2H), 2.41 (s, 3H), 3.75 (s, 3H), 5.21 (d, J ¼ 7.5 Hz, 1H), 5.82 (t, J ¼ 7.5 Hz,
1H), 6.03 (d, J ¼ 7.5 Hz, 1H), 6.74 (d, J ¼ 8.7 Hz, 2H), 7.12 (d, J ¼ 8.7 Hz, 2H), 7.22
(d, J ¼ 8.1 Hz, 2H), 7.38 (t, J ¼ 7.5 Hz, 2H), 7.53 (d, J ¼ 7.5 Hz, 1H), 7.65 (d,
J ¼ 7.5 Hz, 2H), 7.71 (d, J ¼ 8.1 Hz, 2H). 13C NMR (75 MHz, CDCl3) d, ppm:
13.3, 21.5, 23.3, 55.2, 61.2, 113.9, 127.2, 128.2, 128.5, 129.1, 129.4, 130.9, 133.4,
137.1, 137.5, 137.8, 138.0, 143.1, 159.0, 199.1. IR (neat): 3215, 1633, 1511, 1436,
1330, 1243, 1158 cmꢂ1. HRMS (EI) calcd. for C19H20NO2 (MꢂTsþ): 294.1494;
found 294.1493.
Compound 3p. 1H NMR (300 MHz, CDCl3) d, ppm: 0.74 (t, J ¼ 7.5 Hz, 3H),
1.60 ꢂ 1.74 (m, 2H), 2.35 (s, 3H), 3.70 (s, 3H), 3.82 (s, 3H), 5.11 (d, J ¼ 7.5 Hz, 1H),
5.65 (t, J ¼ 7.5 Hz, 1H), 6.04 (d, J ¼ 7.5 Hz, 1H), 6.67 (d, J ¼ 8.4 Hz, 2H), 6.79 (d,
J ¼ 8.7 Hz, 2H), 7.07 (d, J ¼ 8.7 Hz, 2H), 7.16 (d, J ¼ 8.1 Hz, 2H), 7.58 (d, J ¼ 8.7 Hz,
2H), 7.65 (d, J ¼ 8.1 Hz, 2H). 13C NMR (75 MHz, CDCl3) d, ppm: 13.3, 21.4, 23.2,
55.2, 55.5, 61.5, 113.78, 113.80, 127.2, 128.1, 129.4, 130.3, 130.9, 131.7, 136.8, 137.0,
137.9, 143.0, 158.9, 164.0, 197.6. IR (neat): 3278, 1600, 1509, 1421, 1341, 1253, 1161,
1094 cmꢂ1. HRMS (EI) calcd. for C20H22NO3 (MꢂTsþ): 324.1600; found 324.1598.
Compound 3q. 1H NMR (300 MHz, CDCl3) d, ppm: 0.78 (t, J ¼ 7.5 Hz, 3H),
1.63 ꢂ 1.79 (m, 2H), 2.39 (s, 3H), 3.73 (s, 3H), 5.18 (d, J ¼ 8.1 Hz, 1H), 5.81 (t,
J ¼ 7.8 Hz, 1H), 6.03 (d, J ¼ 8.1 Hz, 1H), 6.70 (d, J ¼ 8.4 Hz, 2H), 7.05 (d, J ¼ 8.4 Hz,
2H), 7.18 (d, J ¼ 8.1 Hz, 2H), 7.47 ꢂ 7.51 (m, 4H), 7.66 (d, J ¼ 8.1 Hz, 2H). 13C NMR
(75 MHz, CDCl3) d, ppm: 13.3, 21.5, 23.3, 55.2, 60.9, 113.9, 127.2, 128.2, 128.8,
129.4, 130.6, 130.7, 131.9, 136.2, 137.0, 137.7, 137.9, 143.2, 159.1, 198.0. IR (neat):
3313, 2929, 1635, 1581, 1510, 1399, 1340, 1252 cmꢂ1. HRMS (EI) calcd. for
C19H19NO2Br (MꢂTsþ): 372.0599; found 372.0598.
Compound 3r. 1H NMR (300 MHz, CDCl3) d, ppm: 0.94 (t, J ¼ 7.5 Hz, 3H),
2.05 (s, 3H), 2.14 (m, 2H), 2.39 (s, 3H), 3.75 (s, 3H), 5.10 (d, J ¼ 8.7 Hz, 1H), 5.65 (d,
J ¼ 8.7 Hz, 1H), 5.73 (t, J ¼ 7.5 Hz, 1H), 6.73 (d, J ¼ 8.7 Hz, 2H), 7.03 (d, J ¼ 8.7 Hz,
2H), 7.21 (d, J ¼ 8.1 Hz, 2H), 7.64 (d, J ¼ 8.1 Hz, 2H). 13C NMR (75 MHz, CDCl3) d,
ppm: 13.8, 21.6, 23.1, 31.9, 55.4, 61.0, 114.0, 127.3, 128.0, 129.5, 131.2, 138.1, 139.1,
141.3, 143.2, 159.1, 203.4. IR (neat): 3284, 1660, 1608, 1511, 1424, 1335, 1249 cmꢂ1
HRMS (EI) calcd. for C14H18NO2 (MꢂTsþ): 232.1338; found 232.1342.
.
Compound 3s. 1H NMR (300 MHz, CDCl3) d, ppm: 0.76 (t, J ¼ 7.5 Hz, 3H),
1.60 ꢂ 1.70 (m, 2H), 2.39 (s, 3H), 3.85 (s, 3H), 2.17 (d, J ¼ 7.5 Hz, 1H), 5.66 (t,
J ¼ 7.8 Hz, 1H), 6.30 (d, J ¼ 7.5 Hz, 1H), 6.83 (d, J ¼ 9.0 Hz, 2H), 7.13 ꢂ 7.17 (m,
4H), 7.19 (d, J ¼ 8.1 Hz, 2H), 7.58 (d, J ¼ 8.7 Hz, 2H), 7.66 (d, J ¼ 8.1 Hz, 2H).

REACTION OF N-TOSYLATED IMINES
1951
13C NMR (75 MHz, CDCl3) d, ppm: 13.2, 21.5, 23.4, 55.6, 61.6, 113.9, 127.2, 128.3,
128.6, 129.5, 131.7, 132.2, 133.4, 136.3, 137.5, 137.8, 138.0, 143.3, 164.2, 197.3. IR
(neat): 3278, 1647, 1596, 1491, 1421, 1334, 1258 cmꢂ1. HRMS (EI) calcd. for
C19H19NO2Cl (MꢂTsþ): 328.1104; found 328.1099.
Compound 3t. 1H NMR (300 MHz, CDCl3) d, ppm: 0.76 (t, J ¼ 7.5 Hz, 3H),
1.63 ꢂ 1.73 (m, 2H), 2.38 (s, 3H), 5.15 (d, J ¼ 7.8 Hz, 1H), 5.75 (t, J ¼ 7.8 Hz, 1H),
5.97 (d, J ¼ 7.8 Hz, 1H), 6.99 ꢂ 7.26 (m, 8H), 7.56 ꢂ 7.65 (m, 4H). 13C NMR
(75 MHz, CDCl3) d, ppm: 13.2, 21.5, 23.5, 61.2, 115.8, 116.1, 127.2, 128.4, 129.1,
129.5, 131.8, 132.0, 133.6, 136.4, 137.3, 137.7, 138.8, 143.5, 197.2. IR (KBr): 3303,
1625, 1605, 1510, 1421, 1385, 1342, 1253 cmꢂ1. HRMS (EI) calcd. for C18H16NOFCl
(MꢂTsþ): 318.0885; found 318.0882.
Compound 3u. 1H NMR (300 MHz, CDCl3) d, ppm: 0.74 (t, J ¼ 7.5 Hz, 3H),
1.56 ꢂ 1.75 (m, 2H), 2.36 (s, 6H), 5.52 (d, J ¼ 7.5 Hz, 1H), 5.58 (t, J ¼ 8.1 Hz, 1H),
6.38 (d, J ¼ 7.5 Hz, 1H), 7.03 ꢂ 7.22 (m, 6H), 7.27 ꢂ 7.35 (m, 2H), 7.49 (d, J ¼ 8.1 Hz,
2H), 7.69 (d, J ¼ 8.4 Hz, 2H). 13C NMR (75 MHz, CDCl3) d, ppm: 13.2, 21.5, 21.8,
23.5, 58.9, 127.1, 127.3, 128.9, 129.1, 129.2, 129.3, 129.4, 129.5, 132.4, 134.3, 134.7,
136.0, 137.4, 138.7, 143.2, 144.8, 198.9. IR (neat): 3286, 1654, 1603, 1444, 1338, 1239,
1162 cmꢂ1. HRMS (EI) calcd. for C19H19NOCl (MꢂTsþ): 312.1155; found 312.1152.
Compound 3v. 1H NMR (300 MHz, CDCl3) d, ppm: 0.74 (t, J ¼ 7.5 Hz, 3H),
1.60 ꢂ 1.71 (m, 2H), 2.34 (s, 3H), 5.49 (d, J ¼ 7.5 Hz, 1H), 5.61 (t, J ¼ 7.5 Hz, 1H),
6.15 (d, J ¼ 7.5 Hz, 1H), 7.05 ꢂ 7.20 (m, 6H), 7.41–7.47 (m, 4H), 7.65 (d, J ¼ 8.1 Hz,
2H).13C NMR (75 MHz, CDCl3) d, ppm: 13.2, 21.5, 23.4, 58.9, 115.7, 116.0, 127.2,
127.4, 129.1, 129.2, 129.5, 129.6, 131.8, 131.9, 132.4, 134.2, 135.8, 137.4, 139.0, 143.3,
197.7. IR (neat): 3284, 1660, 1583, 1444, 1335, 1160 cmꢂ1. HRMS (EI) calcd. for
C18H16NOClBr (MꢂTsþ): 376.0104; found 376.0107.
ACKNOWLEDGMENTS
We are grateful to the National Natural Science Foundation of China
(20572104) and the program of New Century Excellent Talents in University
(NCET) (060551) for financial support.
REFERENCES
1. Lee, V. J. In Comprehensive Organic Synthesis; B. M. Trost, I. Fleming (Eds.); Pergamon:
Oxford, 1991; vol. 4, pp. 139–168.
2. Mori, M.; Kuroda, S.; Dekura, F. Formation of silazirconacyclopentene via zirconium–
silene complex and alkyne. J. Am. Chem. Soc. 1999, 121, 5591–5592.
3. (a) Denmark, S. E.; Choi, J. Y. Highly stereospecific, cross-coupling reactions of
alkenylsilacyclobutanes. J. Am. Chem. Soc. 1999, 121, 5821–5822; (b) Maezaki, N.;
Sawamoto, H.; Yoshigami, R.; Suzuki, T.; Tanaka, T. Geometrically selective synthesis
of functionalized b,b-disubstituted vinylic sulfoxides by Cu-catalyzed conjugate addition
of organozinc reagents to 1-alkynyl sulfoxides. Org. Lett. 2003, 5, 1345–1347.
4. (a) Roth, F.; Gygax, P.; Frater, G. An intramolecular Baylis–Hillman reaction.
Tetrahedron Lett. 1992, 33, 1045–1048; (b) Drewes, S. E.; Njamela, O. L.; Emslie, N.

1952
Y.-K. LIU ET AL.
D.; Ramesar, N.; Field, J. S. Intramolecular Baylis–Hillman reaction: A pathway to
substituted coumarins. Synth. Commun. 1993, 23, 2807–2815.
5. Reviews for the MBH reaction: (a) Basavaiah, D.; Darma, R. P.; Hyma, R. S. The Baylis–
Hillman reaction: A novel carbon–carbon bond-forming reaction. Tetrahedron 1996, 52,
8001–8062; (b) Langer, P. New strategies for the development of an asymmetric version
of the Baylis–Hillman reaction. Angew. Chem. Int. Ed. 2000, 39, 3049–3052; (c) Basavaiah,
D.; Rao, A. J.; Satyanarayana, T. Recent advances in the Baylis–Hillman reaction and
applications. Chem. Rev. 2003, 103, 811–892; (d) Kataoka, T.; Kinoshita, H. Chalcogenide–
Lewis acid–mediated tandem Michael aldol reaction: An alternative to the Morita–Baylis–
Hillman reaction and a new development. Eur. J. Org. Chem. 2005, 45–58.
6. (a) Trost, B. M.; Pinkerton, A. B. A ruthenium-catalyzed three-component coupling to
form (E)-vinyl chlorides. J. Am. Chem. Soc. 1999, 121, 1988–1989; (b) Trost, B. M.;
Pinkerton, A. B. A mechanistic dichotomy leading to a ruthenium-catalyzed cis-addition
for stereoselective formation of (Z)-vinyl bromides. Angew. Chem. Int. Ed. 2000, 39,
360–362.
7. Marino, J. P.; Linderman, R. J. Chemistry of substituted (a-carbethoxyvinyl)cuprates 2:
Stereospecific olefin synthesis. J. Org. Chem. 1983, 48, 4621–4628.
8. (a) Wei, H. X.; Willis, S.; Li, G. Lewis acid–promoted carbonyl addition of lithium
(a-carbalkoxyvinyl)cuprates to aldehydes provides a novel asymmetric synthesis of
b,b-disubstituted a-(hydroxyalkyl)acrylates. Tetrahedron. Lett. 1998, 39, 8203–8206; (b)
Wei, H. X.; Willis, S.; Li, G. Z=E selective synthesis of b,b-disubstituted and (Z)-b-
monosubstituted Baylis–Hillman adducts via anionic additions of vinylcuprates to
aldehydes. Synth. Commun. 1999, 29, 2959–2966.
9. (a) Wei, H. X.; Hook, J. D.; Fitzgerald, K. A.; Li, G. Asymmetric synthesis of
b-monosubstituted and b,b-disubstituted N-(p-toluenesulfinyl)-a-(aminoalkyl)acrylates
via anionic additions of (a-carbalkoxyvinyl)cuprates to thiooxime S-oxides. Tetrahedron:
Asymmetry 1999, 10, 661–665; (b) Li, G.; Wei, H. X.; Whittlesey, B. R.; Bartrice, N. N.
Novel asymmetric C–C bond-formation process promoted by Et2AlCl and its application
to the stereoselective synthesis of unusual b-branched Baylis–Hillman adducts. J. Org.
Chem. 1999, 64, 1061–1064; (c) Li, G.; Kim, S. H.; Wei, H. X. Highly efficient deprotec-
tion of N-p-toluenesulfinyl group of b-branched Baylis–Hillman adducts by using
amberlite IR-120 (plus) ion-exchange resin. Tetrahedron 2000, 56, 719–723.
10. (a) Ramachandran, P. V.; Reddy, M. V. R.; Rudd, M. T.; Alaniz, J. R. Vinylalumination
of fluoro-carbonyl compounds. Tetrahedron Lett. 1998, 39, 8791–8794; (b)
Ramachandran, P. V.; Ram Reddy, M. V.; Rudd, M. T. Vinylalumination of activated
carbonyl compounds. Tetrahedron Lett. 1999, 40, 627–630; (c) Ramachandran, P. V.;
Ram Reddy, M. V.; Rudd, M. T. An improved vinylalumination procedure replacing
HMPA with NMO for the hydroalumination of a-acetylenic esters and ketones. Chem.
Commun. 1999, 1979–1980; (d) Li, G.; Wei, H. X.; Willis, S. A new stereospecific synthesis
of unusual (Z)-b-branched Baylis–Hillman adducts. Tetrahedron Lett. 1998, 39,
4607–4610; (e) Chen, D. J.; Timmons, C.; Liu, J. Y.; Hendley, A.; Li, G. The first enan-
tioselective halo aldol reaction of ethyl propiolate and aldehydes. Eur. J. Org. Chem. 2004,
3330–3335.
11. For conjugate addition of zinc–copper reagents to acetylenic esters, see (a) Knochel, P.;
Singer, R. D. Preparation and reactions of polyfunctional organozinc reagents in organic
synthesis. Chem. Rev. 1993, 93, 2117–2188; (b) Knoess, H. P.; Furlong, M. T.; Rozema,
M. J.; Knochel, P. Preparation and reactions of zinc and copper organometallics bearing
acidic hydrogens. J. Org. Chem. 1991, 56, 5974–5978; (c) Jubert, C.; Knochel, P.
Preparation of new classes of aliphatic, allylic, and benzylic zinc and copper reagents
by the insertion of zinc dust into organic halides, phosphates, and sulfonates. J. Org.
Chem. 1992, 57, 5425–5431.

REACTION OF N-TOSYLATED IMINES
1953
12. For conjugate addition of organozinc reagents to acetylenic ketones, see (a) Brunner, M.;
Maas, G. Conjugate addition-reactions of functionalized organozinc and copper reagents
to (2-propynylidene)morpholinium triflates. Synthesis 1995, 957–963; (b) Nakamura, E.;
Kuwajima, I. Copper-catalyzed acylation and conjugate addition of zinc homoenolate:
Synthesis of 4- and 5-oxo esters. J. Am. Chem. Soc. 1984, 106, 3368–3370.
13. (a) Xue, S.; He, L.; Han, K. Z.; Liu, Y. K.; Guo, Q. X. Stereoselective synthesis of
b-branched Baylis–Hillman adducts via organozinc species. Synlett 2005, 8, 1247–1250;
(b) Xue, S.; He, L.; Liu, Y. K.; Guo, Q. X. An efficient CuI-promoted synthesis of
tri- and tetra-substituted alkenes using organozinc species. Synthesis 2006, 666–674.
14. Lorenz, J. C.; Jiang, L.; Yang, Z. Q.; Xue, S.; Xie, Y. N.; Shi, Y. A novel class of tunable
zinc reagents (RXZnCH2Y) for efficient cyclopropanation of olefins. J. Org. Chem. 2004,
69, 327–334.
15. Kitamura, M.; Miki, T.; Noyori, R. 1,4-Addition of diorganozincs to a,b-unsaturated
ketones catalyzed by a copper(I)-sulfonamide combined system. Bull. Chem. Soc. Jpn.
2000, 73, 999–1014.
16. (a) Taniguchi, M.; Hino, T.; Kishi, Y. A practical synthesis of trans-iodoolefins. Tetra-
hedron Lett. 1986, 27, 4759–4762; (b) Kinoshita, S.; Kinoshita, H.; Iwamura, T.;
Watanabe, S.; Kataoka, T. Chalcogenide–Lewis acid–mediated reactions of electron-
deficient alkynes with aldehydes. Chem. Eur. J. 2003, 9, 1496–1502.

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