Efficient Catalytic Asymmetric Epoxidation
J. Am. Chem. Soc., Vol. 119, No. 46, 1997 11233
mixture was cooled to about -10 °C (inside) (outside temperature was
about -12 to -15 °C) via a NaCl-ice bath. A solution of Oxone
(0.85 g, 1.38 mmol) in aqueous Na2(EDTA) (4 × 10-4 M, 6.5 mL)
and a solution of K2CO3 (0.8 g, 5.8 mmol) in water (6.5 mL) were
added dropwise separately over a period of 2 h (via syringe pumps or
addition funnels). The reaction was then worked up by the same
procedure as in method B to afford trans-â-methylstyrene oxide (0.126
g, 94% yield, 95.5% ee).
trans-Stilbene Oxide (Table 4, Entry 1). White crystals: mp 68-
70 °C (recrystallized from hexane), [R]25D ) +356.1° (c 0.95, benzene)
(Table 4, entry 1, method C at 0 °C); -358.1° (c 0.82, benzene) [Table
4, entry 1, method C (ent-1)] [lit.23a mp 68-69 °C, [R]D ) +361° (c
2.05, benzene) for (R, R)-form].
Epoxide. Colorless oil: [R]25D ) +40.5° (c 1.2, CHCl3); IR (KBr)
3058, 3028, 2983, 2889, 1606, 1495, 1468, 1380, 1148, 1115, 944,
756, 699 cm-1; 1H NMR δ 7.4-7.2 (m, 5H), 5.02 (d, J ) 3.6 Hz, 1H),
4.12-3.91 (m, 4H), 3.90 (d, J ) 2.1 Hz, 1H), 3.15 (dd, J ) 3.6, 2.1
Hz, 1H); 13C NMR δ 136.5, 128.7, 128.6, 126.0, 102.6, 65.77, 65.59,
61.58, 55.47; HRMS calcd for C11H12O3 (M+) 192.0786, found
192.0783.
(R,R)-2-Methyl-3-(2-methylphenyl)oxirane (Table 4, Entry 7).
The olefin substrate was prepared from o-methylbenzyltriphenylphos-
phonium bromide and acetaldehyde by Wittig reaction with a ratio of
1
trans/cis ) 2.3 (determined by H NMR). trans-Olefin: 1H NMR δ
7.41-7.09 (m, 4H), 6.59 (dq, J ) 15.6, 1.8 Hz), 6.10 (dq, J ) 15.6,
6.6 Hz, 1H), 2.33 (s, 3H), 1.90 (dd, J ) 6.6, 1.8 Hz). cis-Olefin: 1H
NMR δ 7.41-7.09 (m, 4H), 6.45 (dq, J ) 11.4, 1.8 Hz, 1H), 5.82 (dq,
J ) 11.4, 6.9 Hz), 2.25 (s, 3H), 1.74 (dd, J ) 6.9, 1.8 Hz, 3H).
trans-â-Methylstyrene oxide (Table 4, Entry 2). Colorless oil:
[R]25D ) +47.8° (c 1.04, CHCl3) (Table 4, entry 2, method C); -46.9°
(c 0.88, CHCl3) [Table 4, entry 2, method C (ent-1)] [lit.23b +47.2° (c
1.10, CHCl3) for (R)-form].
Epoxides. trans/cis ) 2.33 (determined by GC). trans-Epoxide
(purified from cis-epoxide): colorless oil, [R]25 ) +29.4° (c 0.32,
D
(R,R)-2-[(tert-Butyldimethylsiloxy)methyl]-3-phenyloxirane (Table
4, Entry 3). The olefin substrate was prepared from cinnamyl alcohol
and tert-butyldimethylsilyl chloride28 to give a colorless oil: IR (KBr)
3060, 3027, 2954, 2931, 2856, 1656, 1599, 1495, 1467, 1379, 1254,
benzene); IR (KBr) 3062, 3024, 2967, 2927, 1606, 1490, 1458, 1378,
1
1020, 956, 862, 747 cm-1; H NMR δ 7.3-7.2 (m, 4H), 3.71 (d, J )
2.1 Hz, 1H), 2.92 (dq, J ) 5.1, 2.1 Hz, 1H), 2.4 (s, 3H), 1.48 (d, J )
5.1 Hz, 3H); 13C NMR δ 136.2, 135.9, 129.9, 127.6, 126.3, 124.3, 58.22,
57.77, 19.02, 18.17. cis-Epoxide: 1H NMR δ 7.3-7.2 (m, 4H), 4.04
(d, J ) 4.5 Hz, 1H), 3.41 (dq, J ) 5.4, 4.5 Hz, 1H), 2.33 (s, 3H), 1.01
(d, J ) 5.4 Hz, 3H); 13C NMR δ 135.8, 134.0, 129.7, 127.4, 126.7,
125.7, 56.68, 54.69, 18.86, 13.06. Anal. Calcd for C10H12O (trans
and cis): C, 81.04; H, 8.16. Found: C, 81.21; H 8.16.
1
1125, 1073, 964, 834, 777, 729, 690 cm-1; H NMR δ 7.36-7.1 (m,
5H), 6.54 (dt, J ) 15.9, 1.8 Hz, 1H), 6.23 (dt, J ) 15.9, 5.1 Hz, 1H),
4.3 (dd, J ) 5.1, 1,8 Hz, 2H), 0.89 (s, 9H), 0.062 (s, 6H); 13C NMR δ
137.3, 129.7, 129.3, 128.7, 127.5, 126.6, 64.06, 26.18, 18.65, -4.947.
Epoxide. Colorless oil: [R]25D ) +39.7° (c 1.0, CH2Cl2) (Table 4,
entry 3, method C); IR (KBr) 3062, 3030, 2954, 2931, 2857, 2890,
1605, 1498, 1464, 1385, 1254, 1138, 1106, 1050, 887, 836, 778, 697
(R,R)-2-Isopropyl-3-(2-methylphenyl)oxirane (Table 4, Entry 8).
The olefin substrate was prepared from o-methylbenzyltriphenylphos-
phonium bromide and isobutyraldehyde via Wittig reaction with a ratio
1
cm-1; H NMR δ 7.4-7.2 (m, 5H), 3.97 (dd, J ) 12, 3.3 Hz, 1H),
1
of trans/cis ) 4.1 (determined by H NMR). trans-Olefin: 1H NMR
3.82 (dd, J ) 12.0, 4.2 Hz, 1H), 3.8 (d, J ) 2.4 Hz, 1H), 3.14 (ddd, J
) 4.2, 3.3, 2.4 Hz, 1H), 0.92 (s, 9H), 0.13 (s, 3H), 0.12 (s, 3H); 13C
NMR δ 137.5, 128.7, 128.3, 125.9, 63.24, 62.94, 56.11, 26.1, 18.61,
-5.06; HRMS calcd for C15H22O2Si (M+ - 1) 263.1465, found
263.1467.
δ 7.44-7.1 (m, 4H), 6.53 (d, J ) 15.7 Hz, 1H), 6.05 (dd, J ) 15.7,
6.6 Hz, 1H), 2.48 (m, J ) 6.6 Hz, 1H), 2.33 (s, 3H), 1.10 (d, J ) 6.6
Hz, 6H). cis-Olefin: 1H NMR δ 7.44-7.10 (m, 4H), 6.29 (d, J )
11.4 Hz, 1H), 5.51 (dd, J ) 11.4, 10.2 Hz, 1H), 2.62 (m, 1H), 2.25 (s,
3H), 0.98 (d, J ) 6.6 Hz, 3H).
(R,R)-2-Phenyl-3-[(triphenylmethoxy)methyl]oxirane (Table 4,
Entry 4). The olefin substrate was prepared from cinnamyl alcohol
and triphenylmethyl chloride29 to give white crystals: mp 122-124
°C (recrystallized from hexane); IR (KBr) 3057, 3027, 2925, 2853,
Epoxides. trans/cis ) 3.8 (determined by GC). trans-Epoxide
(purified from cis-epoxide): colorless oil. [R]25 ) -21.2° (c 0.6,
D
benzene); IR (KBr) 3062, 3025, 2962, 2872, 1606, 1491, 1463, 1382,
1366, 1043, 945, 895, 750 cm-1; 1H NMR δ 7.3-7.1 (m, 4H), 3.79 (d,
J ) 2.1 Hz, 1H), 2.62 (dd, J ) 6.9, 2.1 Hz, 1H), 2.39 (s, 3H), 1.69 (m,
1H), 1.11 (d, J ) 6.6 Hz, 3H), 1.06 (d, J ) 6.6 Hz, 3H); 13C NMR δ
136.4, 135.7, 129.9, 127.6, 126.3, 67.86, 56.05, 31.19, 19.43, 19.06,
18.69. cis-Epoxide: 1H NMR δ 7.3-7.2 (m, 4H), 4.07 (d, J ) 4.2
Hz, 1H), 2.94 (dd, J ) 8.4, 4.2 Hz, 1H), 2.36 (s, 3H), 1.61 (m, 1H),
1.1 (d, J ) 6.6 Hz, 3H), 0.71 (d, J ) 6.6 Hz, 3H); 13C NMR δ 135.6,
134.2, 129.7, 127.3, 126.2, 125.6, 65.1, 56.94, 26.37, 20.24, 18.96,
18.46. Anal. Calcd for C12H16O (trans and cis): C, 81.77; H, 9.15.
Found: C, 81.80; H, 9.36.
1661, 1597, 1490, 1446, 1219, 1103, 1056, 965, 743, 700 cm-1 1H
.
NMR δ 7.55-7.2 (m, 20H), 6.7 (dt, J ) 15.9, 1.8 Hz, 1H), 6.3 (dt, J
) 15.9, 5.4 Hz, 1H), 3.78 (dd, J ) 5.4, 1.8 Hz, 2H); 13C NMR δ 144.3,
137.3, 130.8, 128.8, 128.7, 128.1, 128.0, 127.6, 127.2, 126.8, 126.6,
87.12, 65.07.
Epoxide. White crystals: mp 116-118 °C (recrystallized from
hexane); [R]25D ) +34.1° (c 0.74, CHCl3); IR (KBr) 3056, 3025, 2925,
1
2863, 1598, 1491, 1448, 1220, 1083, 748 cm-1; H NMR δ 7.5-7.2
(m, 20H), 3.78 (d, J ) 1.8 Hz, 1H), 3.45 (m, 1H), 3.26 (m, 2H); 13C
NMR δ 144.0, 137.3, 128.9, 128.7, 128.4, 128.1, 127.3, 125.9, 87.05,
64.38, 61.53, 56.36. Anal. Calcd for C28H24O2: C, 85.68; H, 6.16.
Found: C, 85.47; H, 6.40.
(R,R)-2-[(tert-Butyldimethylsiloxy)methyl]-3-propyloxirane (Table
4, Entry 9). The olefin substrate was prepared from trans-2-hexen-
1-ol and tert-butyldimethylsilyl chloride28 to give a colorless oil: IR
(KBr) 2957, 2931, 2858, 1671, 1465, 1381, 1255, 1104, 1062, 969.
(2S,3R)-2-(Chloromethyl)-3-phenyloxirane (Table 4, Entry 5).
Colorless oil: [R]25D ) +26.2° (c 0.9, CHCl3) (Table 4, entry 5, method
C); IR (KBr) 3055, 3033, 2990, 1604, 1497, 1460, 1265, 930, 878,
1
838, 776 cm-1; H NMR δ 5.65 (dt, J ) 15.3, 6.3 Hz, 1H), 5.53 (dt,
1
748, 697 cm-1; H NMR δ 7.35-7.15 (m, 5H), 3.77 (d, J ) 2.1 Hz,
J ) 15.3, 5.1 Hz, 1H), 4.13 (d, J ) 5.1 Hz, 2H), 2.01 (dt, J ) 6.6, 6.3
Hz, 2H), 1.4 (m, J ) 7.5, 6.6 Hz, 2H), 0.91 (t, J ) 7.5 Hz, 3H), 0.914
(s, 9H), 0.075 (s, 6H); 13C NMR δ 131.5, 129.5, 64.31, 34.54, 26.2,
22.59, 18.65, 13.91, -4.89.
1H), 3.66 (dd, J ) 12, 5.1 Hz, 1H), 3.60 (dd, J ) 12.0, 5.7 Hz, 1H),
3.22 (ddd, J ) 5.7, 5.1, 2.1 Hz, 1H); 13C NMR δ 136.1, 128.8, 128.8,
125.9, 61.18, 58.76, 44.56; HRMS calcd for C9H9ClO (M+) 168.0342,
170.0312 (37Cl), found 168.0349, 170.0312 (37Cl).
Epoxide. Colorless oil: [R]25 ) +17.7° (c 0.74, CHCl3) (Table
D
(2S,3R)-2-(Ethylenedioxymethyl)-3-phenyloxirane (Table 4, Entry
6). The olefin substrate was prepared by ketalization of cinnamyl
aldehyde with ethylene glycol30 to give a colorless oil: IR (KBr) 3058,
3028, 2956, 2885, 1677, 1600, 1493, 1451, 1394, 1148, 1063, 961,
4, entry 9, method C); IR (KBr) 2957, 2932, 2859, 1467, 1254, 1129,
1095, 838, 778, 665 cm-1 1H NMR δ 3.78 (dd, J ) 11.7, 3.4 Hz,
.
1H), 3.67 (dd, J ) 11.7, 4.5 Hz, 1H), 2.87-2.79 (m, 2H), 1.6-1.4 (m,
4H), 0.96 (t, J ) 7.2 Hz, 3H), 0.90 (s, 9H), 0.078 (s, 3H), 0.069 (s,
3H); 13C NMR δ 63.9, 58.85, 56.43, 33.94, 26.08, 19.51, 18.56, 14.11,
-5.076, -5.133; HRMS calcd for C12H25O2Si (M+ - 1) 229.1623,
found 229.1618.
1
749, 693 cm-1; H NMR δ 7.45-7.2 (m, 5H), 6.78 (d, J ) 15.9 Hz,
1H), 6.17 (dd, J ) 15.9, 6.0 Hz, 1H), 6.43 (d, J ) 6.0 Hz, 1H), 4.1-
3.9 (m, 4H); 13C NMR δ 135.9, 135.0, 128.7, 128.5, 127.0, 125.2, 103.9,
65.13.
(R,R)-2-[1-(tert-Butyldimethylsiloxy)ethyl]-3-ethyloxirane (Table
4, Entry 10). The olefin substrate was prepared from trans-3-hexen-
1-ol and tert-butyldimethylsilyl chloride28 to give a colorless oil: IR
(28) Corey, E. J.; Venkakeswarlu, A. J. Am. Chem. Soc. 1972, 94, 6190-
6191.
(29) Chaudlrary, S. K.; Hernandez, O. Tetrahedron Lett. 1979, 95-98.
(30) Daignault, R. A.; Eliel, E. L. Organic Syntheses; Wiley: New York,
1973; Collect Vol. V, pp 303-306.
(KBr) 2957, 2931, 2858, 1468, 1384, 1254, 1103, 966, 836, 776 cm-1
;
1H NMR δ 5.53 (dt, J ) 15.3, 6.0 Hz, 1H), 5.39 (dt, J ) 15.3, 6.6 Hz,
1H), 3.62 (t, J ) 6.9 Hz, 1H), 2.21 (dt, J ) 6.9, 6.6 Hz, 1H), 2.01 (m,