Lewis base effects in the Baylis-Hillman reaction of imines with methyl vinyl ketone

Article abstract of DOI:10.1002/1099-0690(200202)2002:4<696::AID-EJOC696>3.0.CO;2-N

In the Baylis-Hillman reaction of N-benzylidene-4-methyl-benzenesulfonamide with methyl vinyl ketone (MVK), we found that, in the presence of a catalytic amount of DMAP, PPh₃ or DABCO as Lewis base, the Baylis-Hillman reaction can be greatly ac

Full text of DOI:10.1002/1099-0690(200202)2002:4<696::AID-EJOC696>3.0.CO;2-N

FULL PAPER
Lewis Base Effects in the Baylis؊Hillman Reaction of Imines with
Methyl Vinyl Ketone
Min Shi*[a] and Yong-Mei Xu[a]
Keywords: BaylisϪHillman reaction / Schiff bases / Lewis bases
In the Baylis−Hillman reaction of N-benzylidene-4-methyl-
adducts 1 in good or very high yields. However, with PBu3
benzenesulfonamide with methyl vinyl ketone (MVK), we as a Lewis base, the abnormal Baylis−Hillman adducts 2 and
found that, in the presence of a catalytic amount of DMAP,
PPh3 or DABCO as Lewis base, the Baylis−Hillman reaction
can be greatly accelerated to give the normal Baylis−Hillman
3 were formed under the same reaction conditions. The effect
of the substituents was also examined and a plausible reac-
tion mechanism proposed.
Introduction
ined systematically (Scheme 1, Table 1). We found that the
reaction proceeds very well with 20 mol % of DABCO,
DMAP or PPh3 as a Lewis base, to give the normal
BaylisϪHillman adduct 1a in moderate to good yields
(Table 1, entry 1Ϫ2, 6). The Lewis base PPh3 gave the best
results, whereas DBU, NEt3 and SMe2 showed no activity
in this reaction (Table 1, entry 4Ϫ5). However, using PBu3
as a Lewis base gave two unexpected adducts 2a and 3a
(abnormal BaylisϪHillman adducts) and no formation of
the normal BaylisϪHillman adduct 1a was observed
(Scheme 1, Table 1, entry 7). The structures of 2a and 3a
were established by spectroscopic data and X-ray analyses
(Figure 1 and 2).[6,7] The two aryl groups in 2a are in syn-
form (Figure 2). The use of 2.0 equiv. of N-(4-ethylbenzylid-
ene)-4-methylbenzenesulfonamide and 1.0 equiv. of MVK
in the presence of PBu3 did not improve the yields of 2a
and 3a.
The BaylisϪHillman reaction has made great pro-
gress[1] — it now includes a catalytic asymmetric ver-
sion[2] — since Baylis and Hillman first reported the reac-
tion of acetaldehyde with ethyl acrylate and acrylonitrile in
the presence of catalytic amounts of a strong Lewis base
such as 1,4-diazabicyclo[2.2.2]octane (DABCO) in 1972.[3]
During our own investigations on this very simple and use-
ful reaction,[4] we found that in the reaction of aryl alde-
hydes with electron-donating groups such as Et or MeO on
the phenyl ring with methyl vinyl ketone (MVK), the reac-
tions were either sluggish or no reactions occurred under
traditional BaylisϪHillman reaction conditions. Thus, we
decided to use N-benzylidene-4-methylbenzenesulfonam-
ides to replace the aryl aldehydes in the traditional
BaylisϪHillman reaction with methyl vinyl ketone (MVK)
as the CϭN double bond of N-benzylidene-4-methylben-
zenesulfonamides should be more active than the CϭO
double bond of aryl aldehydes. So far, we have only found
one report related to the BaylisϪHillman reaction of MVK
with imines generated in situ at 40 °C for 40 h.[5] Herein,
we wish to report the results on the reactions of N-benzylid-
ene-4-methylbenzenesulfonamides with MVK catalyzed dir-
ectly by Lewis bases such as DABCO, DMAP, PPh3, or
PBu3.
Scheme 1
Results and Discussion
The promoters for the reaction of N-(4-ethylbenzylid-
ene)-4-methylbenzenesulfonamide with MVK were exam-
Similar results were obtained for other N-benzylidene-4-
methylbenzenesulfonamides using PPh3 as a Lewis base un-
der the optimized reaction conditions (Scheme 2). The nor-
mal BaylisϪHillman adducts were obtained in good yields.
These results are summarized in Table 2.
[a]
State Key Laboratory of Organometallic Chemistry,
Shanghai Institute of Organic Chemistry, Chinese Academy of
Sciences,
354 Fenglin Lu, Shanghai 200032, China
Fax: (internat.) ϩ86-21/416-3300
E-Mail: mshi@pub.sioc.ac.cn
Abnormal BaylisϪHillman adducts can be obtained ex-
clusively under the same reaction conditions for other N-
696
WILEY-VCH Verlag GmbH, 69451 Weinheim, Germany, 2002 1434Ϫ193X/02/0204Ϫ0696 $ 17.50ϩ.50/0 Eur. J. Org. Chem. 2002, 696Ϫ701

Lewis Base Effects in the BaylisϪHillman Reaction
FULL PAPER
Table 1. BaylisϪHillman reactions of N-(4-ethylbenzylidene)-4-
methylbenzenesulfonamide (1.0 equiv.) with methyl vinyl ketone
(1.0 equiv.) in the presence of Lewis base (20 mol %)
Entry Promoter
Solvent Time (h) 1a[a] 2a[a] [b] 3[a] [b]
1
2
3
4
5
6
7
8
DMAP
DABCO
DMAP
DMF
DMF
THF
48
48
24
48
48
24
9
40
36
40
trace
trace
80
0
0
0
0
0
0
0
0
0
0
0
0
0
0
25
DBU or NEt3 THF
Scheme 2
SMe2
PPh3
dppe
PBu3
THF
THF
THF
THF
56
2
trace 60
Table 2. BaylisϪHillman reactions of N-(4-ethylbenzylidene)-4-
methylbenzenesulfonamide (1.0 equiv.) with methyl vinyl ketone
(1.0 equiv.) in the presence of PPh3 (20 mol %)
[a]
[b]
Isolated yield (%). Yield based on imine.
Entry
Ar
Yield of 1 (%)
1
2
3
4
5
6
7
8
9
C6H5
75
92
70
80
80
45
82
87
78
67
p-MeC6H4
p-MeOC6H4
p-ClC6H4
p-BrC6H4
2,3-Cl2C6H3
p-NO2C6H4
m-FC6H4
2-furyl
10
C6H4-CHϭCH
Figure 1. The crystal structure of 2a
Scheme 3
Table 3. Abnormal BaylisϪHillman reactions of N-(4-ethylbenzyli-
dene)-4-methylbenzenesulfonamide (1.0 equiv.) with methyl vinyl
ketone (2.0 equiv.) in the presence of PBu3 (20 mol %)
Entry
Ar
Time (h)
Yield of 2
Yield of 3
(%)
(%)[a]
1
2
3
4
5
6
7
8
C6H5
2
2
2
2
2
2
2
2
31
48
65
29
16
Ϫ
48
28
20
43
43
Ϫ
p-MeC6H4
p-MeOC6H4
p-ClC6H4
p-FC6H4
2,3-Cl2C6H3
m-FC6H4
2-furyl
Figure 2. The crystal structure of 3a
18
42
44
19
benzylidene-4-methylbenzenesulfonamides with MVK us-
ing PBu3 as a Lewis base in THF (Scheme 3). These results
are summarized in Table 3. The total yields of abnormal
BaylisϪHillman adducts in general reached 75%. N-tosyl-
[a]
Based on imine.
ated imines with electron-donating groups gave 2 as the ma- dichloro-substituted imine (Table 3, entry 6). We confirmed
jor product (Table 3, entries 1Ϫ3, 8), whereas imines with that 2a and 3a were formed independently during the reac-
electron-withdrawing groups gave 3 as the major product tion as 2a cannot be transformed into 3a under the reaction
(Table 3, entries 4, 5, 7). No reaction occurred with the 2,3- conditions. N-tosylated imines can react with methyl acryl-
Eur. J. Org. Chem. 2002, 696Ϫ701
697

M. Shi, Y.-M. Xu
FULL PAPER
used without purification. All N-tosyl imines were prepared ac-
cording to the literature. Infrared spectra were measured on a
PerkinϪElmer 983 spectrometer. 1H NMR spectra were recorded
on a 300 MHz spectrometer in CDCl3 using tetramethylsilane as
the internal standard. Mass spectra were recorded with an HP-5989
instrument and the HRMS were measured on a Finnigan MAϩ
mass spectrometer. Satisfactory CHN microanalyses were obtained
with a CarloϪErba 1106 analyzer. Melting points were obtained
with a micro melting point apparatus and are uncorrected.
ate or acrylonitrile under the same conditions, but the cor-
responding 2 and 3 were obtained in very low yields.
In Scheme 4, we tentatively propose a reaction mechan-
ism for the formation of 2 and 3. We believe that the differ-
ence of nucleophilicity between triphenylphosphane (PPh3)
and tributylphosphane (PBu3) is the key factor for the dif-
ferent reaction products shown in Scheme 2 and 3. Using
PPh3 as the Lewis base (a weaker Lewis base), the corres-
ponding BaylisϪHillman reaction intermediate A, which
immediately gives the normal BaylisϪHillman adduct 1 by
an E1cb mechanism, is relatively difficult to form and thus
requires a longer reaction time (24 h). With PBu3 as the
Lewis base (a stronger Lewis base), the easily formed cor-
responding intermediate A can attack the next imine to give
the cyclized products (the reactions are generally complete
within 2 h). This plausible reaction mechanism is supported
by a known phosphane-catalyzed [3ϩ2] cycloaddition of
methyl 2,3-butadienoate and N-tosylimines.[8]
Typical Reaction Procedure for Triphenylphosphane-Catalyzed
Baylis؊Hillman Reaction of Methyl Vinyl Ketone and an N-(4-
Ethylbenzylidene)-4-methylbenzenesulfonamide. Synthesis of 1a:
Methyl vinyl ketone (41 µl, 0.5 mmol) was added to a solution of
N-(4-ethylbenzylidene)-4-methylbenzenesulfonamide
(144 mg,
0.5 mmol) and triphenylphosphane (26 mg, 0.1 mmol) in THF
(1.0 mL) at room temperature. After stirring for 24 h at room
temperature, the solvent was removed under reduced pressure and
the residue was purified by flash chromatography (SiO2, EtOAc/
petroleum ether, 1:5) to yield 1a (142 mg, 80%) as a colorless solid
which was recrystallized from acetone and n-hexane. M.p. 126Ϫ128
Ϫ1
1
˜
°C. IR (CHCl3): ν ϭ 1674 cm (CϭO). H NMR (CDCl3, TMS,
300 MHz): δ ϭ 1.23 (t, J ϭ 7.6 Hz, 3 H, Me), 2.15 (s, 3 H, Me),
2.39 (s, 3 H, Me), 2.54 (q, J ϭ 7.6 Hz, 2 H, CH2), 5.20 (d, J ϭ
6.1 Hz, 1 H, NH), 5.51 (d, J ϭ 8.4 Hz, 1 H, CH), 6.09 (s, 2 H),
6.97 (d, J ϭ 6.1 Hz, 2 H, Ar), 6.98 (2 H, J ϭ 6.1 Hz, Ar), 7.21 (d,
J ϭ 8.4 Hz, 2 H, Ar), 7.63 (d, J ϭ 8.4 Hz, 2 H). MS (EI): m/z
(%) ϭ 358 (0.5) [Mϩ Ϫ 1], 288 (5.6) [Mϩ Ϫ 69], 202 (100) [Mϩ
Ϫ
155] . C20H23NO3S (357.5): calcd. C 67.2, H 6.49, N 3.92; found C
67.04, H 6.42, N 3.74.
1b: Isolated as a colorless solid from the reaction of MVK with
N-benzylidene-4-methylbenzenesulfonamide; m.p. 113Ϫ114 °C. IR
Ϫ1
(CϭO). 1H NMR (CDCl3, TMS,
˜
(CHCl3): ν ϭ 1667 cm
300 MHz): δ ϭ 2.16 (s, 3 H, Me), 2.42 (s, 3 H, Me), 5.26 (d, J ϭ
8.6 Hz, 1 H), 5.61 (d, J ϭ 8.6 Hz, 1 H), 6.10 (s, 1 H), 6.11 (s, 1 H),
7.11 (m, 2 H, Ar), 7.20Ϫ7.27 (m, 5 H, Ar), 7.66 (d, J ϭ 8.1 Hz, 2
H, Ar). MS (EI): m/z (%) ϭ 260 (14.09) [Mϩ Ϫ 69], 174 (100) [Mϩ
Ϫ 155], 155 (29.60) [MePhSO2ϩ]. C18H19NO3S (329.4): calcd. C
65.63, H 5.81, N 4.25; found C 65.64, H 5.74, N 4.14.
1c: Isolated as a colorless solid from the reaction of MVK with N-
(4-methylbenzylidene)-4-methylbenzenesulfonamide; m.p. 118Ϫ119
Ϫ1
°C. IR (KBr): ν ϭ 1664 cm (CϭO). 1H NMR (CDCl3, TMS,
˜
Scheme 4
300 MHz): δ ϭ 2.16 (s, 3 H, Me), 2.27 (s, 3 H, Me), 2.42 (s, 3 H,
Me), 5.23 (d, J ϭ 8.4 Hz, 1 H), 5.56 (d, J ϭ 8.4 Hz, 1 H), 6.10 (s,
2 H), 6.95 (d, J ϭ 8.2 Hz, 2 H, Ar), 7.00 (d, J ϭ 8.2 Hz, 2 H, Ar),
7.24 (d, J ϭ 8.2 Hz, 2 H, Ar), 7.65 (d, J ϭ 8.2 Hz, 2 H, Ar). MS
(EI): m/z (%) ϭ 274 (4.44) [Mϩ Ϫ 69], 188 (100) [Mϩ Ϫ 155], 91
(50.98) [PhMeϩ]. C19H21NO3S (343.4): calcd. C 66.47, H 6.12, N
4.08; found C 66.74, H 6.47, N 3.89.
In conclusion, we have found that in the BaylisϪHillman
reaction of N-benzylidene-4-methylbenzenesulfonamides
with MVK, the Lewis bases play a very important role.
Normal BaylisϪHillman adducts were obtained using
DMAP, DABCO or PPh3 (20 mol %) as the Lewis base,
whereas abnormal BaylisϪHillman adducts were formed
exclusively using PBu3 (20 mol %) as the Lewis base. Efforts
are underway to elucidate the mechanistic details of this
reaction and to determine the scope and limitations of
this reaction.
1d: Isolated as a colorless solid from the reaction of MVK with
N-(4-methoxybenzylidene)-4-methylbenzenesulfonamide;
m.p.
Ϫ1
(CϭO). 1H NMR
˜
136Ϫ137 °C. IR (CHCl3): ν ϭ 1675 cm
(CDCl3, TMS, 300 MHz): δ ϭ 2.17 (s, 3 H, Me), 2.41 (s, 3 H, Me),
3.74 (s, 3 H, Me), 5.21 (d, J ϭ 8.3 Hz, 1 H, NH), 5.49 (d, J ϭ
8.3 Hz, 1 H, CH), 6.10 (s, 2 H), 6.73 (d, J ϭ 6.8 Hz, 2 H, Ar), 6.99
(d, J ϭ 6.8 Hz, 2 H, Ar), 7.25 (d, J ϭ 9.3 Hz, 2 H, Ar), 7.65 (d,
J ϭ 9.3 Hz, 2 H, Ar). MS (EI): m/z (%) ϭ 359 (0.30) [Mϩ], 290
(9.61) [Mϩ Ϫ 69], 204 (100) [Mϩ Ϫ 155], 91 (45.58) [PhMeϩ].
C19H21NO4S (359.4): calcd. C 63.49, H 5.89, N 3.90; found C
63.24, H 5.81, N 3.73.
Experimental Section
General Remarks: Unless otherwise stated, all reactions were car-
ried out under an argon atmosphere. All solvents were purified by
distillation. Methyl vinyl ketone and tributylphosphane were ob- 1e: Isolated as a colorless solid from the reaction of MVK with N-
tained from Tokyo Chemical Industry (Tokyo Kasei Co. Ltd.) and
698
(4-chlorobenzylidene)-4-methylbenzenesulfonamide; m.p.112Ϫ113
Eur. J. Org. Chem. 2002, 696Ϫ701

Lewis Base Effects in the BaylisϪHillman Reaction
FULL PAPER
1
°C. IR (CHCl3): ν˜ ϭ 1674 cmϪ1 (CϭO). H NMR (CDCl3, TMS, 129Ϫ130 °C. IR (CHCl3): ν˜ ϭ 1667 cmϪ1 (CϭO). 1H NMR
300 MHz): δ ϭ 2.11 (s, 3 H, Me), 2.38 (s, 3 H, Me), 5.24 (d, J ϭ (CDCl3, TMS, 300 MHz): δ ϭ 2.19 (s, 3 H, Me), 2.33 (s, 3 H, Me),
9.1 Hz, 1 H, NH), 5.99 (d, J ϭ 9.1 Hz, 1 H, CH), 6.03 (s, 1 H), 4.77 (dd, J ϭ 8.8, 7.3 Hz, 1 H, CH), 5.62 (d, J ϭ 8.8 Hz, 1 H, NH),
6.06 (s, 1 H,), 7.01(d, J ϭ 8.6 Hz, 2 H, Ar), 7.12 (d, J ϭ 8.6 Hz, 2 6.00 (m, 3 H), 6.25 (d, J ϭ 15.9 Hz, 1 H), 7.14Ϫ7.26 (m, 7 H, Ar),
H, Ar), 7.19 (d, J ϭ 8.1 Hz, 2 H, Ar), 7.59 (d, J ϭ 8.1 Hz, 2 H, 7.66 (d, J ϭ 7.9 Hz, 2 H, Ar). MS (EI): m/z (%) ϭ 286 (3.08) [Mϩ
Ar). MS (EI): m/z (%) ϭ 294 (2.36) [Mϩ Ϫ 69], 208 (100) [Mϩ
Ϫ
Ϫ 69], 200 (100) [Mϩ Ϫ 155], 157 (34.73) [Mϩ Ϫ 198]. C20H21NO3S
155], 91 (39.81) [PhMeϩ]. C18H18ClNO3S (363.9): calcd. C 59.42, (355.5): calcd. C 67.58, H 5.95, N 3.94; found C 67.41, H 6.06,
H 4.99, N 3.85; found C 59.43, H 4.94, N 3.78.
N 3.68.
1f: Isolated as a colorless solid from the reaction of MVK with N-
(4-bromobenzylidene)-4-methylbenzenesulfonamide; m.p. 115Ϫ116
Typical Reaction Procedure for the Tributylphosphane-Catalyzed
Baylis؊Hillman Reaction of Methyl Vinyl Ketone and an N-(4-
Ethylbenzylidene)-4-methylbenzenesulfonamide. Synthesis of 2a and
3a: Methyl vinyl ketone (41 µl, 0.5 mmol) was added to a solution
of N-(4-ethylbenzylidene)-4-methylbenzenesulfonamide (144 mg,
0.5 mmol) and tributylphosphane (25 µl) in THF (1.0 mL) at room
temperature. The reaction was monitored by TLC. After stirring
for 2 h the solvent was removed under reduced pressure. The res-
idue was purified by flash chromatography (SiO2, EtOAc/petro-
leum ether, 1:10Ϫ1:5) to yield 2a (71 mg, 60%) and 3a (20 mg, 25%)
as solids that were recrystallized from acetone and n-hexane, re-
spectively.
1
°C. IR (CHCl3): ν˜ ϭ 1674 cmϪ1 (CϭO). H NMR (CDCl3, TMS,
300 MHz): δ ϭ 2.16 (s, 3 H, Me), 2.42 (s, 3 H, Me), 5.20 (d, J ϭ
8.9 Hz, 1 H), 5.71 (d, J ϭ 8.9 Hz, 1 H), 6.06 (s, 1 H), 6.10 (s, 1 H),
6.99 (d, J ϭ 6.7 Hz, 2 H, Ar), 7.24 (d, J ϭ 8.4 Hz, 2 H, Ar), 7.32
(d, J ϭ 6.7 Hz, 2 H, Ar), 7.63 (d, J ϭ 8.4 Hz, 2 H, Ar). MS (EI):
m/z (%) ϭ 252 (92.12) [Mϩ Ϫ 155], 254 (85.18) [Mϩ Ϫ 153], 130
(100) [Mϩ Ϫ 277], 91 (73.41) [PhMeϩ]. C18H18BrNO3S (408.3):
calcd. C 52.94, H 4.41, N 3.43; found C 52.96, H 4.46, N 3.42.
1g: Isolated as a colorless solid from the reaction of MVK with
N-(2,3-dichlorobenzylidene)-4-methylbenzenesulfonamide;
m.p.
2a: Colorless solid; m.p. 151Ϫ152 °C. IR (CHCl3): ν˜ ϭ 1676 cmϪ1
(CϭO). 1H NMR (CDCl3, TMS, 300 MHz): δ ϭ 1.21 (t, J ϭ
7.6 Hz, 3 H, Me), 1.24 (t, J ϭ 7.6 Hz, 3 H, Me), 2.17 (s, 3 H, Me),
2.30 (s, 3 H, Me), 2.60 (q, J ϭ 7.6 Hz, 2 H, CH2), 2.65 (q, J ϭ
7.6 Hz, 2 H, CH2), 5.84 (t, J ϭ 2.6 Hz, 1 H, CH), 5.93 (dd, J ϭ
2.6, 2.1 Hz, 1 H), 6.62 (t, J ϭ 2.1 Hz, 1 H, CH), 6.99 (d, J ϭ
8.2 Hz, 2 H, Ar), 7.08 (d, J ϭ 8.2 Hz, 2 H, Ar), 7.16 (d, J ϭ 6.4 Hz,
2 H, Ar), 7.19 (d, J ϭ 6.4 Hz, 2 H, Ar), 7.25 (d, J ϭ 8.1 Hz, 2 H,
Ar), 7.28 (d, J ϭ 8.1 Hz, 2 H, Ar). MS (EI): m/z (%) ϭ 473 (3.9)
[Mϩ], 318 (100) [Mϩ Ϫ 155], 276 (98) [Mϩ Ϫ 197]. C29H31NO3S
(473.6): calcd. C 73.54, H 6.60, N 2.96; found C 73.60, H 6.61,
N 2.78.
96Ϫ98 °C. IR (KBr): ν˜ ϭ 1672 cmϪ1 (CϭO). 1H NMR (CDCl3,
TMS, 300 MHz): δ ϭ 2.22 (s, 3 H, Me), 2.38 (s, 3 H, Me), 5.69 (d,
J ϭ 8.6 Hz, 1 H), 5.79 (d, J ϭ 8.6 Hz, 1 H), 6.12 (s, 1 H), 6.17 (s,
1 H), 7.05 (dd, J ϭ 8.0, 7.8 Hz, 1 H, Ar), 7.18 (d, J ϭ 8.2 Hz, 2
H, Ar), 7.28 (m, 2 H, Ar), 7.62 (d, J ϭ 8.2 Hz, 2 H, Ar). MS (EI):
m/z (%) ϭ 242 (5.00) [Mϩ Ϫ 155], 171 (65.36) [Mϩ Ϫ 226], 91 (100)
[PhMeϩ]. C18H17Cl2NO3S·1/6C6H14·1/6C3H6O (422.3): calcd. C
55.50, H 4.82, N 3.32; found C 56.09, H 5.30, N 3.03.
1h: Isolated as a pale-yellow solid from the reaction of MVK
with N-(4-nitrobenzylidene)-4-methylbenzenesulfonamide; m.p.
140Ϫ142 °C. IR (CHCl3): ν˜ ϭ 1674 cmϪ1 (CϭO). 1H NMR
(CDCl3, TMS, 300 MHz): δ ϭ 2.15 (s, 3 H, Me), 2.44 (s, 3 H, Me),
5.32 (d, J ϭ 9.4 Hz, 1 H), 5.94 (d, J ϭ 9.4 Hz, 1 H), 6.08 (s, 1 H),
6.14 (s, 1 H), 7.25 (d, J ϭ 8.3 Hz, 2 H, Ar), 7.34 (d, J ϭ 8.7 Hz, 2
H, Ar), 7.65 (d, J ϭ 8.3 Hz, 2 H, Ar), 8.07 (d, J ϭ 8.7 Hz, 2 H).
MS (EI): m/z (%) ϭ 305 (3.77) [Mϩ Ϫ 69], 219 (100) [Mϩ Ϫ 155],
155 (29.96) [MePhSO2ϩ]. C18H18N2O5S (374.4): calcd. C 57.74, H
4.85, N 7.48; found C 57.62, H 4.84, N 7.39.
3a: Yellow solid; m.p. 163Ϫ165 °C. IR (CHCl3): ν˜ ϭ 1645 cmϪ1
(CϭO). 1H NMR (CDCl3, TMS, 300 MHz): δ ϭ 1.26 (t, J ϭ
7.5 Hz, 3 H, Me), 1.28 (t, J ϭ 7.5 Hz, 3 H, Me), 2.34 (s, 3 H, Me),
2.65 (q, J ϭ 7.5 Hz, 2 H, CH2), 2.68 (q, J ϭ 7.5 Hz, 2 H, CH2),
6.92(1 H,d, J ϭ 2.9 Hz), 7.25 (d, J ϭ 8.2 Hz, 2 H, Ar), 7.29 (d,
J ϭ 8.2 Hz, 2 H, Ar), 7.41 (d, J ϭ 8.2 Hz, 2 H, Ar), 7.53 (d, J ϭ
8.2 Hz, 2 H, Ar), 8.42 (1 H, br, s, NH). MS (EI): m/z (%) ϭ 317
(90.7) [Mϩ], 302 (100) [Mϩ Ϫ 15]. C22H23NO (317.4): calcd. C
83.24, H 7.43, N 4.41; found C 83.00, H 7.30, N 4.22.
1i: Isolated as a colorless solid from the reaction of MVK with
N-(3-fluorobenzylidene)-4-methylbenzenesulfonamide; m.p. 98Ϫ99
1
°C. IR (CHCl3): ν˜ ϭ 1673 cmϪ1 (CϭO). H NMR (CDCl3, TMS,
2b: Isolated as a colorless solid from the reaction of MVK with N-
benzylidene-4-methylbenzenesulfonamide; m.p. 79Ϫ81 °C. IR
(KBr): ν˜ ϭ 1674 cmϪ1 (CϭO). 1H NMR (CDCl3, TMS, 300 MHz):
δ ϭ 2.19 (s, 3 H, Me), 2.31 (s, 3 H, Me), 5.90 (t, J ϭ 2.6 Hz, 1 H),
5.97 (dd, J ϭ 2.6, 1.8 Hz, 1 H), 6.65 (dd, J ϭ 2.6, 1.8 Hz, 1 H),
7.02 (d, J ϭ 8.1 Hz, 2 H, Ar), 7.21Ϫ7.28 (m, 6 H, Ar), 7.31Ϫ7.36
(m, 6 H, Ar). MS (EI): m/z (%) ϭ 417 (7.07) [Mϩ], 262 (94.74) [Mϩ
Ϫ 155], 220 (100) [Mϩ Ϫ 197]. C25H23NO3S (417.5): calcd. C 72.27,
H 5.09, N 3.37; found C 72.01, H 5.29, N 3.32.
300 MHz): δ ϭ 2.16 (s, 3 H, Me), 2.41 (s, 3 H, Me), 5.24 (d, J ϭ
9.2 Hz, 1 H, NH), 5.78 (d, J ϭ 9.2 Hz, 1 H), 6.06 (s, 1 H), 6.11 (s,
1 H), 6.79Ϫ6.92 (m, 3 H, Ar), 7.14Ϫ7.23 (m, 3 H, Ar), 7.65 (d,
J ϭ 8.6 Hz, 2 H, Ar). MS (EI): m/z (%) ϭ 278 (7.84) [Mϩ Ϫ 69],
192 (100) [Mϩ Ϫ 155], 155 (44.33) [MePhSO2ϩ]. C18H18FNO3S
(347.4): calcd. C 62.23, H 5.22, N 4.03; found C 62.38, H 5.34,
N 3.82.
1j: Isolated as a colorless solid from the reaction of MVK with N-
(furan-2-ylmethylene)-4-methylbenzenesulfonamide; m.p. 114Ϫ115
Ϫ1
1
3b: Isolated as a yellow solid from the reaction of MVK with N-
benzylidene-4-methylbenzenesulfonamide; m.p. 192Ϫ193 °C. IR
˜
°C. IR (CHCl3): ν ϭ 1673 cm (CϭO). H NMR (CDCl3, TMS,
300 MHz): δ ϭ 2.21 (s, 3 H, Me), 2.41 (s, 3 H, Me), 5.35 (d, J ϭ
9.2 Hz, 1 H, NH), 5.70 (d, J ϭ 9.2 Hz, 1 H), 6.00 (d, J ϭ 3.2 Hz,
1 H, Ar), 6.08 (s, 1 H), 6.11 (s, 1 H), 6.19 (dd, J ϭ 3.2, 1.8 Hz, 1
H, Ar), 7.18 (d, J ϭ 1.8 Hz, 1 H, Ar), 7.26 (d, J ϭ 8.6 Hz, 2 H),
7.68 (d, J ϭ 8.6 Hz, 2 H, Ar). MS (EI): m/z (%) ϭ 250 (2.77) [Mϩ
(KBr): ν ϭ 1627 cmϪ1 (CϭO). 1H NMR (CDCl3, TMS, 300 MHz):
˜
δ ϭ 2.35 (s, 3 H, Me), 6.96(t, J ϭ 2.8 Hz, 1 H), 7.29 (d, J ϭ 6.2 Hz,
1 H, Ar), 7.39Ϫ7.54 (m, 5 H, Ar), 7.53 (d, J ϭ 8.9 Hz, 2 H, Ar),
7.62 (d, J ϭ 6.2 Hz, 2 H, Ar), 8.60 (1 H, br, s, NH). MS (EI): m/z
(%) ϭ 261 (66.60) [Mϩ], 246 (100) [Mϩ Ϫ 15]. C18H15NO (261.3):
calcd. C 82.73, H 5.79, N 5.36; found C 82.72, H 5.48, N 5.17.
Ϫ
69], 164 (52.53) [Mϩ 155], 155 (40.56) [MePhSO2ϩ].
Ϫ
C16H17NO4S (319.4): calcd. C 60.17, H 5.37, N 4.39; found C
60.23, H 5.33, N 4.19.
2c: Isolated as a colorless solid from the reaction of MVK with N-
1k: Isolated as a pale-yellow solid from the reaction of MVK
with 4-methyl-N-(3-phenylallylidene)benzenesulfonamide; m.p.
(4-methylbenzylidene)-4-methylbenzenesulfonamide; m.p. 132Ϫ133
Ϫ1
°C. IR (KBr): ν ϭ 1675 cm (CϭO). 1H NMR (CDCl3, TMS,
˜
Eur. J. Org. Chem. 2002, 696Ϫ701
699

M. Shi, Y.-M. Xu
FULL PAPER
300 MHz): δ ϭ 2.17 (s, 3 H, Me), 2.30 (s, 3 H, Me), 2.32 (s, 3 H, 3f: Isolated as a yellow solid from the reaction of MVK with N-
Me), 2.34 (s, 3 H, Me), 5.80 (t, J ϭ 2.5 Hz, 1 H), 5.88 (dd, J ϭ (4-fluorobenzylidene)-4-methylbenzenesulfonamide: m.p. 205Ϫ206
Ϫ1
2.5, 1.9 Hz, 1 H), 6.60 (dd, J ϭ 2.5, 1.9 Hz, 1 H), 7.03Ϫ7.12 (m, 6
°C. IR (KBr): ν ϭ 1634 cm (CϭO). 1H NMR (CDCl3, TMS,
˜
H), 7.23Ϫ7.30 (m, 6 H). MS (EI): m/z (%) ϭ 445 (7.89) [Mϩ], 290 300 MHz): δ ϭ 2.37 (s, 3 H, Me), 6.87 (d, J ϭ 3.0 Hz, 1 H), 7.12
(100) [Mϩ Ϫ 155], 274 (67.94) [Mϩ Ϫ 171]. C27H27NO3S (445.6): (d, J ϭ 6.8 Hz, 2 H, Ar), 7.16 (d, J ϭ 6.8 Hz, 2 H, Ar), 7.48 (m, 2
calcd. C 72.81, H 6.07, N 3.15; found C 73.01, H 6.30, N 2.98.
H, Ar), 7.60 (m, 2 H, Ar), 8.48 (br. s, 1 H, NH). MS (EI): m/z (%) ϭ
297 (69.19) [Mϩ], 282 (100) [Mϩ Ϫ 15]. C18H13F2NO (297.3): calcd.
C 72.72, H 4.41, N 4.71; found C 72.53, H 4.28, N 4.33.
3c: Isolated as a yellow solid from the reaction of MVK with N-
(4-methylbenzylidene)-4-methylbenzenesulfonamide; m.p. 206Ϫ207
Ϫ1
°C. IR (KBr): ν ϭ 1627 cm (CϭO). 1H NMR (CDCl3, TMS,
2h: Isolated as a colorless solid from the reaction of MVK with N-
˜
(4-nitrobenzylidene)-4-methylbenzenesulfonamide: m.p. 126Ϫ127
300 MHz): δ ϭ 2.32 (s, 3 H, Me), 2.36 (s, 3 H, Me), 2.40 (s, 3 H,
Me), 6.90(d, J ϭ 2.9 Hz, 1 H), 7.19 (d, J ϭ 8.1 Hz, 2 H, Ar), 7.25
(d, J ϭ 8.1 Hz, 2 H, Ar), 7.40 (d, J ϭ 8.1 Hz, 2 H, Ar), 7.48 (d,
J ϭ 8.1 Hz, 2 H, Ar), 8.53 (br. s, 1 H, NH). MS (EI): m/z (%) ϭ
289 (87.84) [Mϩ], 274 (100) [Mϩ Ϫ 15]. C20H19NO (289.4): calcd.
C 83.04, H 6.57, N 4.84; found C 82.99, H 6.49, N 4.57.
Ϫ1
°C. IR (KBr): ν ϭ 1673 cm (CϭO). 1H NMR (CDCl3, TMS,
˜
300 MHz): δ ϭ 2.29 (s, 2 H, Me), 2.47 (s, 2 H, Me), 5.88 (t, J ϭ
2.5 Hz, 1 H, CH), 5.92 (dd, J ϭ 2.5, 1.2 Hz, 1 H, CH), 6.65 (dd,
J ϭ 2.5, 1.2 Hz, 1 H), 6.94Ϫ7.36 (m, 12 H, Ar). MS (EI): m/z
(%) ϭ 453 (18.93) [Mϩ], 298 (100) [Mϩ Ϫ 155]. C25H21F2NO3S
(453.5): calcd. C 66.21, H 4.67, N 3.09; found C 66.44, H 4.88,
N 2.91.
2d: Isolated as a colorless solid from the reaction of MVK
with N-(4-methoxybenzylidene)-4-methylbenzenesulfonamide; m.p.
116Ϫ117 °C. IR (KBr): ν˜ ϭ 1675 cmϪ1 (CϭO). 1H NMR (CDCl3,
TMS, 300 MHz): δ ϭ 2.19 (s, 3 H, Me), 2.33 (s, 3 H, Me), 3.77 (s,
3 H, Me), 3.80 (s, 3 H, Me), 5.80 (t, J ϭ 2.4 Hz, 1 H, CH), 5.89
(dd, J ϭ 2.4, 1.8 Hz, 1 H, CH), 6.62 (dd, J ϭ 2.4, 1.8 Hz, 1 H),
6.76Ϫ6.87 (m, 4 H, Ar), 7.05 (d, J ϭ 7.9 Hz, 2 H), 7.22 (m, 6 H,
Ar). MS (EI): m/z (%) ϭ 477 (21.60) [Mϩ], 322 (96.31) [Mϩ Ϫ 155],
306 (100) [Mϩ Ϫ 197]. HRMS calcd. for C27H27NO5S requires
477.1610 [Mϩ]; found 477.1584.
3h: Isolated as a yellow solid from the reaction of MVK with N-(4-
nitrobenzylidene)-4-methylbenzenesulfonamide: m.p. 205Ϫ206 °C.
IR (KBr): ν˜ ϭ 1622 cmϪ1 (CϭO). 1H NMR (CDCl3, TMS,
300 MHz): δ ϭ 2.40 (s, 3 H, Me), 6.95 (d, J ϭ 3.0 Hz, 1 H),
7.01Ϫ7.44 (m, 8 H, Ar). MS (EI): m/z (%) ϭ 297 (72.04) [Mϩ], 282
(100) [Mϩ Ϫ 15]. C18H13F2NO (297.3): calcd. C 72.72, H 4.41, N
4.71; found C72.80, H 4.23, N 4.48.
2i: Isolated as a black viscous oil from the reaction of MVK with
N-(3-fluorobenzylidene)-4-methylbenzenesulfonamide. IR (KBr):
3d: Isolated as a yellow solid from the reaction of MVK with N-(4-
methoxybenzylidene)-4-methylbenzenesulfonamide; m.p. 186Ϫ188
°C. IR (KBr): ν˜ ϭ 1627 cmϪ1 (CϭO). 1H NMR (CDCl3, TMS,
300 MHz): δ ϭ 2.41 (s, 3 H, Me), 3.85 (s, 3 H, Me), 3.87 (s, 3 H,
Me), 6.85 (m, 1 H), 6.94 (d, J ϭ 6.7 Hz, 2 H, Ar), 6.97 (d, J ϭ
6.7 Hz, 2 H, Ar), 7.44 (d, J ϭ 8.0 Hz, 2 H, Ar), 7.53 (d, J ϭ 8.0 Hz,
2 H, Ar), 8.57 (br. s, 1 H, NH). MS (EI): m/z (%) ϭ 321 (100)
[Mϩ], 306 (78.84) [Mϩ Ϫ 155]. HRMS calcd. for C20H19NO3 re-
quires 321.1365 [Mϩ]; found 321.1325.
Ϫ1
1
˜
ν ϭ 1648 cm (CϭO). H NMR (CDCl3, TMS, 300 MHz): δ ϭ
2.30 (s, 2 H, Me), 2.37 (s, 2 H, Me), 5.97 (t, J ϭ 2.5 Hz, 1 H, CH),
6.10 (dd, J ϭ 2.5, 1.8 Hz, 1 H, CH), 6.23Ϫ6.35 (m, 4 H, Ar), 6.62
(dd, J ϭ 2.5, 1.8 Hz, 1 H), 7.03 (d, J ϭ 8.6 Hz, 2 H, Ar), 7.17Ϫ7.34
(m, 4 H, Ar). MS (EI): m/z (%) ϭ 330 (27.28) [Mϩ Ϫ 67], 242 (100)
[Mϩ Ϫ 155]. HRMS calcd. for C21H19NO5S requires 397.0984
[Mϩ]; found 397.0967.
3i: Isolated as a black viscous oil from the reaction of MVK with
N-(3-fluorobenzylidene)-4-methylbenzenesulfonamide. IR (KBr):
1
ν˜ ϭ 1627 cmϪ1 (CϭO). H NMR (CDCl3, TMS, 300 MHz): δ ϭ
2e: Isolated as a colorless solid from the reaction of MVK with N-
(4-chlorobenzylidene)-4-methylbenzenesulfonamide; m.p. 135Ϫ137
2.57 (s, 3 H, Me), 6.50 (m, 3 H, Ar), 6.80 (d, J ϭ 3.1 Hz, 1 H),
7.40 (dd, J ϭ 7.3, 1.9 Hz, 2 H, Ar), 7.77 (d, J ϭ 3.1 Hz, 1 H, Ar).
MS (EI): m/z (%) ϭ 241 (100) [Mϩ], 226 (48.57) [Mϩ Ϫ Me].
HRMS calcd. for C20H19NO3 requires 241.0739 [Mϩ]; found
241.07298.
Ϫ1
°C. IR (KBr): ν ϭ 1648 cm (CϭO). 1H NMR (CDCl3, TMS,
˜
300 MHz): δ ϭ 2.21 (s, 3 H, Me), 2.37 (s, 3 H, Me), 5.88 (t, J ϭ
2.4 Hz, 1 H), 5.90 (dd, J ϭ 2.4, 1.8 Hz, 1 H), 6.62 (dd, J ϭ 2.4,
1.8 Hz, 1 H), 7.09 (d, J ϭ 8.2 Hz, 2 H, Ar), 7.23Ϫ7.32 (m, 10 H,
Ar). MS (EI): m/z (%) ϭ 485 (6.55) [Mϩ], 330 (100) [Mϩ Ϫ 155],
288 (64.31) [Mϩ Ϫ 197]. C25H21Cl2NO3S (486.4): calcd. C 59.42,
H 4.99, N 3.88; found C 59.68, H 4.84, N 3.72.
Acknowledgments
3e: Isolated as a yellow solid from the reaction of MVK with N-
We thank the State Key Project of Basic Research (Project 973)
(No. G2000048007) and the National Natural Science Foundation
of China for financial support (20025206). We also thank the Inoue
Photochirogenesis Project (ERATO, JST) for chemical reagents.
(4-chlorobenzylidene)-4-methylbenzenesulfonamide; m.p. 231Ϫ232
Ϫ1
°C. IR (KBr): ν ϭ 1635 cm (CϭO). 1H NMR (CDCl3, TMS,
˜
300 MHz): δ ϭ 2.39 (s, 3 H, Me), 6.92(d, J ϭ 3.1 Hz, 1 H),
7.37Ϫ7.48 (m, 6 H, Ar), 7.52Ϫ7.56 (m, 2 H, Ar), 8.63 (br. s, 1 H,
NH). MS (EI): m/z (%) ϭ 329 (84.23) [Mϩ], 314 (100) [Mϩ Ϫ 15].
HRMS calcd. for C18H13Cl2NO requires 329.0374 [Mϩ]; found
329.0401.
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[1b]
E. Ciganek, Org. React. 1997, 51, 201Ϫ350.
D. Basa-
vaiah, P. D. Rao, R. S. Hyma, Tetrahedron 1996, 52,
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8001Ϫ8062. [1c] S. E. Drewes, G. H. P. Roos, Tetrahedron 1988,
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[1d]
44, 4653Ϫ4670.
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L. J. Brzezinski, S. Rafel, J. W. Leahy, J.
Ϫ1
°C. IR (KBr): ν ϭ 1648 cm (CϭO). 1H NMR (CDCl3, TMS,
˜
[1e]
T. Miyakoshi, S.
300 MHz): δ ϭ 2.24 (s, 2 H, Me), 2.33 (s, 2 H, Me), 5.86 (t, J ϭ
2.4 Hz, 1 H, CH), 5.93 (t, J ϭ 2.0 Hz, 1 H, CH), 6.62 (t, J ϭ
2.0 Hz, 1 H), 6.91Ϫ7.07 (m, 6 H, Ar), 7.22Ϫ7.35 (m, 6 H, Ar). MS
(EI): m/z (%) ϭ 453 (5.13) [Mϩ], 298 (100) [Mϩ Ϫ 155]. HRMS
calcd. for C25H21F2NO3S requires 453.1210 [Mϩ]; found 453.1187.
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700
Eur. J. Org. Chem. 2002, 696Ϫ701

Lewis Base Effects in the BaylisϪHillman Reaction
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mass: 473.63; crystal color, habit: colorless, prismatic; crystal
dimensions: 0.20 ϫ 0.20 ϫ 0.30 mm; crystal system: mono-
clinic; lattice type: primitive; lattice parameters: a ϭ 12.066(2)
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A, b ϭ 11.913(2) A, c ϭ 18.406(3) A, β ϭ 100.91(1)°, V ϭ
˚
˚
˚
3
˚
2597.8(7) A ; space group: P21/n (no. 14); Z ϭ 4; Dcalcd.
ϭ
[1p]
M. Ono, K. Nishimura, Y. Nagaoka, K. To-
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3
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Eur. J. Org. Chem. 2002, 696Ϫ701
701