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Z. Chai et al. / Tetrahedron: Asymmetry 17 (2006) 2442–2447
4.3.1.4. (4S)-(2-(4-t-Butyl-4,5-dihydrooxazol-2-yl)thio-
phen-3-yl)diphenyl methanol 2d.6 Yield (52%, 222 mg);
colorless viscous oil; ½aꢁD ¼ þ109:4 (c 1.90, CHCl3); H
NMR (CDCl3) d (ppm): 9.69 (s, 1H), 7.32 (m, 11H), 6.30
(d, J = 4.8 Hz, 1H), 4.26 (m, 1H) 4.09 (m, 1H), 3.93 (m,
1H), 0.57 (s, 9H).
4.3.1.9.
(4S)-(2-(4-Benzyl-4,5-dihydrooxazol-2-yl)thio-
phen-3-yl)cyclohexanol 2j. Yield (33%, 118 mg); colorless
29
24
1
1
solid; mp 136–137 ꢁC; ½aꢁD ¼ ꢀ25:0 (c 0.35, CH2Cl2); H
NMR (CDCl3) d (ppm): 7.92 (s, 1H), 7.37–7.11 (m, 7H),
4.62 (m, 1H), 4.37 (m, 1H), 4.15 (m, 1H), 3.14 (dd,
J = 6.0, 13.8 Hz, 1H), 2.78 (dd, J = 7.9, 13.8 Hz, 1H),
2.22–2.10 (m, 2H), 1.96 (m, 2H), 1.54 (m, 5H), 1.26 (m,
1H); 13C NMR (CDCl3) d (ppm): 161.1, 156.5, 137.5,
129.1, 128.6, 128.4, 127.9, 126.6, 123.1, 72.2, 71.1, 68.0,
41.6, 37.5, 25.8, 21.9; IR (film): 2955, 2926, 1640, 1447,
1366, 1240, 752, 702 cmꢀ1; EI-MS: m/z (%): 341 (M+, 6),
284 (14), 91 (16), 77 (10), 40 (100). Anal. Calcd for
C20H23NO2S (%): C, 70.35; H, 6.79; N, 4.10; Found: C,
70.29; H, 6.71; N, 3.81.
4.3.1.5. (4R)-(2-(4-Methylthiomethyl-4,5-dihydrooxazol-
3-yl)thiophen-2-yl)diphenyl methanol 2e. Yield (58.9%,
342 mg); colorless crystal (hexane–diethyl ether); mp 118–
25
1
119 ꢁC; ½aꢁD ¼ þ113:6 (c 0.60, CHCl3); H NMR (CDCl3)
d (ppm): 9.26 (s, 1H), 7.25 (m, 11H), 6.30 (d, J = 5.1 Hz,
1H), 4.39–4.24 (m, 2H), 4.16 (m, 1H), 2.40 (dd, J = 4.4,
13.2 Hz, 1H), 2.00 (s, 3H), 1.89 (dd, J = 8.8, 13.2 Hz,
1H); 13C NMR (CDCl3) d (ppm): 161.0, 154.7, 147.6,
147.0, 132.5, 127.7, 127.6, 127.5, 127.3, 127.0, 126.9,
124.4, 79.1, 72.3, 65.7, 38.0, 15.7; IR (film): 3085, 2959,
1633, 1447, 1418, 750, 701 cmꢀ1; EI-MS: m/z (%): 395
(M+, 67), 318 (32), 215 (100), 105 (66), 77 (32), 61 (76).
Anal. Calcd for C22H21NO2S2 (%): C, 66.80; H, 5.35; N,
3.54; Found: C, 67.00, H, 5.48; N, 3.37.
4.3.1.10.
(4S)-(2-(4-Benzyl-4,5-dihydrooxazol-2-yl)-5-
phenylthiophen-3-yl)diphenyl methanol 2k. Yield (67.4%,
24
228 mg); pale yellow solid; mp 149–151 ꢁC; ½aꢁD ¼ þ89:4
1
(c 1.6, CHCl3); H NMR (CDCl3) d (ppm): 9.33 (s, 1H),
7.44–7.15 (m, 18H), 6.97 (m, 2H), 6.54 (m, 1H), 4.38 (m,
1H), 4.20 (m, 1H), 3.96 (m, 1H), 2.70 (m, 1H), 2.20 (m,
1H); 13C NMR (CDCl3) d (ppm): 160.3, 155.4, 147.3,
147.1, 145.4, 137.4, 133.1, 129.1, 128.9, 128.5, 128.2,
127.7, 127.6, 127.0, 126.5, 126.0, 123.1, 79.3, 72.0, 67.4,
40.7; IR (film): 3060, 2928, 1633, 1601, 1453, 759, 733,
700 cmꢀ1; EI-MS: m/z (%): 501 (M+, 100), 424 (54), 291
(62), 105 (37), 91 (27). Anal. Calcd for C29H27NO2S (%):
C, 79.01; H, 5.43; N, 2.79; Found: C, 78.88; H, 5.69; N, 2.64.
4.3.1.6. (4R)-(2-(4-Benzylthiomethyl-4,5-dihydrooxazol-
3-yl)thiophen-2-yl)diphenyl methanol 2f. Yield (61%,
278 mg); colorless crystal (hexane–ethyl acetate); mp 117–
24
1
118 ꢁC; ½aꢁD ¼ þ72:4 (c 0.65, CHCl3); H NMR (CDCl3)
d (ppm): 9.06 (s, 1H), 7.25 (m, 16H), 6.32 (m, 1H), 4.30
(m, 3H), 3.60 (s, 2H), 2.35 (m, 1H), 1.85 (m, 1H); 13C
NMR (CDCl3) d (ppm): 161.0, 154.8, 147.5, 147.0, 138.0,
132.5, 128.8, 128.6, 127.7, 127.5, 127.3, 127.2, 127.0,
126.9, 124.3, 79.1, 72.4, 65.7, 36.5, 35.3; IR (film): 3085,
4.3.1.11. (4S)-(2-(4-Benzyl-4,5-dihydrooxazol-2-yl)-5-a-
naphthyl thiophen-3-yl)diphenyl methanol 2l. Yield (54.1%,
24
2955, 2921, 1633, 1447, 1417, 1244, 1071, 752, 700 cmꢀ1
;
128 mg); pale yellow solid; mp 137–138 ꢁC; ½aꢁD ¼ þ105:4
ESI-MS (m/z): 471 [M]+. Anal. Calcd for C28H25NO2S2
(%): C, 71.31; H, 5.34; N, 2.97; Found: C, 71.26; H, 5.38;
N, 2.79.
(c 0.65, CHCl3); H NMR (CDCl3) d (ppm): 9.35 (s, 1H),
1
8.07–8.04 (m, 1H), 7.88 (m, 2H), 7.49–7.21 (m, 17H), 7.00
(m, 2H), 6.48 (s, 1H), 4.42 (m, 1H), 4.25 (m, 1H), 4.00 (m,
1H), 2.75 (dd, J = 5.5, 13.8 Hz, 1H), 2.20 (dd, J = 8.1,
13.8 Hz, 1H); 13C NMR (CDCl3) d (ppm): 160.2, 154.6,
147.3, 147.1, 143.3, 137.2, 133.6, 132.6, 131.1, 130.8, 129.0,
128.9, 128.3, 128.2 (5), 128.0, 127.5, 127.4, 126.9, 126.6,
126.3, 126.0, 124.9, 124.8 (7), 79.3, 71.9, 67.2, 40.6; IR (film):
3085, 3059, 3028, 1633, 1447, 751, 732, 700 cmꢀ1; MALDI-
MS (m/z): 552 (M++1). Anal. Calcd for C34H29NOS (%): C,
80.55; H, 5.30; N, 2.54; Found: C, 80.70; H, 5.56; N, 2.35.
4.3.1.7. (4R)-(2-(4-Methylthioethyl-4,5-dihydrooxazol-3-
yl)thiophen-2-yl)diphenyl methanol 2g. Yield (74%,
378 mg); colorless crystal (hexane–diethyl ether); mp 147–
24
1
149 ꢁC; ½aꢁD ¼ þ60:5 (c 0.65, CHCl3); H NMR (CDCl3)
d (ppm): 9.26 (s, 1H), 7.25 (m, 11H), 6.30 (d, J = 5.1 Hz,
1H), 4.39 (m, 1H), 4.22 (m, 1H), 3.91 (m, 1H), 2.35–2.15
(m, 2H), 2.03 (s, 3H), 1.55 (m, 1H), 1.28 (m, 1H); 13C
NMR (CDCl3) d (ppm): 160.2, 154.3, 147.3, 147.1, 132.4,
127.6, 127.5, 127.4 (2), 127.4, 127.1, 126.9, 124.4, 79.0,
72.7, 65.1, 35.1, 30.2, 15.5; IR (film): 3086, 2916, 1636,
1446, 1418, 1240, 1042, 751, 700 cmꢀ1; MALDI-MS (m/
z): 410 [M+1]+. Anal. Calcd for C23H23NO2S2 (%): C,
67.45; H, 5.66; N, 3.42; Found: C, 67.44; H, 5.65; N, 3.29.
4.3.1.12. (4S)-(3-(4-Benzyl-4,5-dihydrooxazol-2-yl)thio-
phen-2-yl)diphenyl methanol 2m. Yield (67%, 108 mg);
colorless crystal (hexane–ethyl acetate); mp 103–105 ꢁC;
22
½aꢁD ¼ þ141:4 (c 0.47, CHCl3); 1H NMR (CDCl3) d
(ppm): 9.46 (s, 1H), 6.98–7.39 (m, 17H), 4.35 (m, 1H),
4.21 (m, 1H), 3.93 (m, 1H), 2.65 (dd, J = 5.4, 13.7 Hz,
1H), 2.0 (dd, J = 8.4, 13.7 Hz, 1H); 13C NMR (CDCl3) d
(ppm): 161.3, 158.2, 147.1, 146.6, 137.4, 129.2, 128.8,
128.3, 127.5, 127.4, 127.3, 127.2, 127.0, 126.2, 125.1,
123.1, 78.3, 71.3, 66.4, 40.5; IR (film): 3085, 3060, 2904,
1644, 1447, 1155, 1024, 980, 754, 699 cmꢀ1; EI-MS: m/z
(%): 426 (M++1, 64), 214 (61), 141 (55), 105 (60), 77
(60), 44 (100). Anal. Calcd for C27H23NO2S (%): C,
76.21; H, 5.45; N, 3.29; Found: C, 76.37; H, 5.44; N, 2.99.
4.3.1.8. (4S)-2-(2-(4-Benzyl-4,5-dihydrooxazol-2-yl)thio-
phen-3-yl)-2-propanol 2i. Yield (74%, 178 mg); colorless
28
1
liquid; ½aꢁD ¼ ꢀ1:15 (c 2.10, CHCl3); H NMR (CDCl3)
d (ppm): 8.33 (s, 1H), 7.30 (m, 6H), 7.08 (m, 1H), 4.65
(m, 1H), 4.35 (m, 1H), 4.15 (m, 1H), 3.20 (m, 1H), 2.80
(m, 1H), 1.64 (m, 6H); 13C NMR (CDCl3) d (ppm):
161.0, 155.6, 137.4, 129.1, 128.6, 128.4, 128.3, 126.7,
123.0, 72.3, 70.3, 68.0, 41.5, 30.4; IR (film): 3229, 2978,
2927, 1633, 1417, 960, 701 cmꢀ1; EI-MS: m/z (%): 301
(M++1, 1), 286 (100), 152 (70), 151 (94), 91 (71); HRMS
(EI) calcd for C15H15NOS2 MH+: 302.1206 0.002, found
302.1209.
4.3.2. Procedure for the preparation of 2h. 0.38 mL
(0.98 mmol, 1.6 M in hexanes) n-BuLi, was added dropwise
to a solution of 1h (200 mg, 0.82 mmol) in Et2O (5 mL) at