3100
M.-Y. Chang et al. / Tetrahedron 63 (2007) 3098–3101
with magnetic stirring. Products in organic solvents were
dried with anhydrous magnesium sulfate before concentra-
tion in vacuo.
gel (hexane/ethyl acetate¼4/1–2/1) afforded compounds
4a–f in 70–82% overall yields.
4.3.1. 2-Propylidene-1-(4-methylphenylsulfonyl)-3,3-di-
phenylpyrrolidine (4a). Viscous gum; IR (CHCl3) 3028,
2953, 1510, 1170, 1041 cmꢀ1; HRMS (ESI, M++1) calcd
for C26H28NO2S 418.1841, found 418.1844; 1H NMR
(300 MHz, CDCl3) d 7.58 (d, J¼8.1 Hz, 2H), 7.21–7.06
(m, 8H), 6.90–6.87 (m, 4H), 5.94 (t, J¼7.5 Hz, 1H), 3.55
(t, J¼6.6 Hz, 2H), 2.59 (t, J¼6.6 Hz, 2H), 2.47 (s, 3H),
1.31–1.20 (m, 2H), 0.66 (t, J¼7.5 Hz, 3H); 13C NMR
(75 MHz, CDCl3) d 143.96, 142.09 (2ꢂ), 141.81, 133.99,
129.38 (2ꢂ), 128.66 (4ꢂ), 128.31 (4ꢂ), 128.17 (2ꢂ),
126.69 (2ꢂ), 114.10, 60.07, 48.63, 41.22, 21.83, 21.25,
14.17. Anal. Calcd for C26H27NO2S: C, 74.79; H, 6.52; N,
3.35. Found: C, 74.92; H, 6.83; N, 3.61.
4.2. 1-(4-Methylphenylsulfonyl)-5,5-diphenylazepan-4-
one (3)
A solution of compound 2 (4.03 g, 10.0 mmol) in dichloro-
methane (100 mL) was added to a stirred solution of
m-chloroperoxybenzoic acid (2.40 g, 75%, 10.4 mmol) in
CH2Cl2 (10 mL). The reaction mixture was stirred at rt for
2 h. The total procedure was monitored by TLC until the
reaction was completed. Without further purification, boron
trifluoride etherate (5 mL) was slowly added to a stirred
solution of the resulting reaction mixture at 0 ꢁC. The reac-
tion mixture was stirred at rt for 15 min. Saturated sodium
bicarbonate solution (10 mL) was added to the reaction
mixture and the solvent was concentrated. The residue was
extracted with ethyl acetate (3ꢂ100 mL). The combined
organic layers were washed with brine, dried, filtered,
and evaporated to afford crude product. Purification on
silica gel (hexane/ethyl acetate¼4/1–2/1) afforded com-
pound 3 (3.48 g, 83%). Mp 144–145 ꢁC; IR (CHCl3) 3019,
4.3.2. 2-(2-Phenylethylidene)-1-(4-methylphenylsul-
fonyl)-3,3-diphenylpyrrolidine (4b). Viscous gum; IR
(CHCl3) 3025, 2917, 1731, 1494, 1163, 1031, 700 cmꢀ1
;
HRMS (ESI, M++1) calcd for C31H30NO2S 480.1997, found
480.2001; 1H NMR (500 MHz, CDCl3) d 7.43 (d, J¼8.0 Hz,
2H), 7.23–7.03 (m, 11H), 6.96–6.94 (m, 4H), 6.85 (d,
J¼7.0 Hz, 2H), 6.16 (t, J¼7.5 Hz, 1H), 3.57 (t, J¼6.5 Hz,
2H), 2.64 (t, J¼6.5 Hz, 2H), 2.52 (d, J¼7.5 Hz, 2H), 2.45
(s, 3H); 13C NMR (125 MHz, CDCl3) d 143.66, 142.22,
141.63 (2ꢂ), 140.79, 133.67, 129.15 (2ꢂ), 128.60 (4ꢂ),
128.34 (2ꢂ), 128.19 (4ꢂ), 128.13 (2ꢂ), 128.01 (2ꢂ),
126.67 (2ꢂ), 125.77, 111.02, 60.09, 48.37, 41.32, 33.37,
21.56. Anal. Calcd for C31H29NO2S: C, 77.63; H, 6.09; N,
2.92. Found: C, 77.75; H, 6.32; N, 2.80.
2918, 1708, 1594, 1493, 1339, 1168, 1090, 756, 699 cmꢀ1
;
HRMS (ESI, M++1) calcd for C25H26NO3S 420.1633,
found 420.1636; H NMR (500 MHz, CDCl3) d 7.64 (d,
1
J¼8.5 Hz, 2H), 7.30–7.23 (m, 8H), 7.07–7.05 (m,
4H), 3.42–3.39 (m, 4H), 2.85–2.80 (m, 4H), 2.44 (s,
3H); 13C NMR (125 MHz, CDCl3) d 208.59, 143.74,
142.44 (2ꢂ), 134.84, 129.84 (2ꢂ), 128.50 (4ꢂ), 128.36
(4ꢂ), 127.23 (2ꢂ), 127.11 (2ꢂ), 64.39, 45.49, 44.67,
42.91, 36.91, 21.52. Anal. Calcd for C25H25NO3S: C,
71.57; H, 6.01; N, 3.34. Found: C, 71.69; H, 6.26; N, 3.68.
Single-crystal X-ray diagram: crystal of compound 3 was
grown by slow diffusion of ethyl acetate into a solution of
compound 3 in dichloromethane to yield colorless prism.
The compound crystallizes in the orthorhombic crystal
4.3.3. 2-[2-(2-Methylphenyl)ethylidene]-1-(4-methylphe-
nylsulfonyl)-3,3-diphenylpyrrolidine (4c). Mp 190–
191 ꢁC; IR (CHCl3) 3019, 2950, 1656, 1598, 1493, 1341,
1161, 1030, 761, 665 cmꢀ1; HRMS (ESI, M++1) calcd
for C32H32NO2S 494.2154, found 494.2155; 1H NMR
(500 MHz, CDCl3) d 7.48 (d, J¼8.0 Hz, 2H), 7.17–7.03
(m, 13H), 6.96 (d, J¼7.5 Hz, 2H), 6.81 (dd, J¼2.5,
6.0 Hz, 1H), 6.15 (t, J¼7.5 Hz, 1H), 3.58 (t, J¼6.5 Hz,
2H), 2.66 (t, J¼6.5 Hz, 2H), 2.46 (s, 3H), 2.46 (d,
J¼7.5 Hz, 2H), 1.95 (s, 3H); 13C NMR (125 MHz,
CDCl3) d 143.71, 142.46, 141.54 (2ꢂ), 138.87, 135.75,
133.91, 129.91, 129.21 (2ꢂ), 128.62 (4ꢂ), 128.26, 128.17
(4ꢂ), 127.99 (2ꢂ), 126.66 (2ꢂ), 125.87, 125.56, 109.64,
60.14, 48.33, 41.23, 30.47, 21.57, 19.21. Anal. Calcd for
C32H31NO2S: C, 77.86; H, 6.33; N, 2.84. Found: C, 77.69;
H, 6.51; N, 2.94.
˚
system. Space group P2(1)2(1)2(1), a¼9.6116(12) A,
3
˚
˚
˚
b¼10.1342(12) A, c¼22.210(3) A, V¼2163.4(5) A , Z¼4,
dcalcd¼1.288 Mg/m3, absorption coefficient 0.176 mmꢀ1
,
F(000)¼888, 2q range (1.83–28.35ꢁ), R indices (all data)
R1¼0.0613, wR2¼0.0889.
4.3. Representative procedure for compounds 4a–f
A solution of methylmagnesium bromide or different aryl-
magnesium bromide reagents (1.0 M in THF, 1 mL,
1.0 mmol) was added to a stirred solution of compound 3
(210 mg, 0.5 mmol) in tetrahydrofuran (20 mL) at ꢀ78 ꢁC.
The reaction mixture was stirred at ꢀ78 ꢁC for 5 h. The total
procedure was monitored by TLC until the reaction was
completed. Without further purification, boron trifluoride
etherate (1 mL) was added to a stirred solution of the result-
ing reaction mixture at 0 ꢁC. The reaction mixture was
stirred at 0 ꢁC for 15 min. Saturated sodium bicarbonate so-
lution (10 mL) was added to the reaction mixture and the sol-
vent was concentrated under reduced pressure. Water (5 mL)
and ethyl acetate (20 mL) were added to the residue and the
mixture was filtered through a short plug of Celite. The fil-
trate was concentrated under reduced pressure. The residue
was extracted with ethyl acetate (3ꢂ20 mL). The combined
organic layers were washed with brine, dried, filtered, and
evaporated to afford crude product. Purification on silica
4.3.4. 2-[2-(2-Methoxyphenyl)ethylidene]-1-(4-methyl-
phenylsulfonyl)-3,3-diphenylpyrrolidine (4d). Viscous
oil; IR (CHCl3) 3923, 2924, 1731, 1493, 1339, 1244,
1161, 1031, 755 cmꢀ1; HRMS (ESI, M++1) calcd for
C32H32NO3S 510.2103, found 510.2105; 1H NMR
(500 MHz, CDCl3) d 7.43 (d, J¼8.5 Hz, 2H), 7.16–7.13
(m, 2H), 7.10–7.06 (m, 6H), 7.02 (d, J¼8.5 Hz, 2H), 6.96–
6.94 (m, 3H), 6.78 (t, J¼7.5 Hz, 2H), 6.63 (dd, J¼1.5,
7.5 Hz, 1H), 6.23 (t, J¼7.5 Hz, 1H), 3.76 (s, 3H), 3.54 (t,
J¼6.5 Hz, 2H), 2.63 (t, J¼6.5 Hz, 2H), 2.50 (d, J¼7.5 Hz,
2H), 2.44 (s, 3H); 13C NMR (125 MHz, CDCl3) d 157.17,
143.46, 141.93, 141.74 (2ꢂ), 133.69, 129.79, 129.06 (2ꢂ),
128.97, 128.72 (4ꢂ), 128.07 (4ꢂ), 128.05 (2ꢂ), 127.08,
126.51 (2ꢂ), 120.03, 110.67, 110.01, 59.97, 55.15, 48.29,