X. Wu et al. / Chinese Chemical Letters 22 (2011) 306–309
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[9] General procedure: To a magnetically stirred slurry of pyridinium chlorochromate (PCC) (97 mg, 0.45 mmol) and silica gel (finer than 200
mesh, 97 mg) in 1 mL 1,2-dichloroethane was added a solution of 15 (65 mg, 0.3 mmol) in 0.5 mL of 1,2-dichloroethane at 85 8C. The resulting
dark red-black mixture was stirred for 5 min and diluted with an equal volume of ether. The following filtration through a pad of silica,
concentration under reduced pressure and purification of the crude residue via silica gel flash column chromatography (gradient eluent: 5–10%
EtOAc in petroleum ether) afforded pure 16 (61 mg) as a yellow oil in 94% yield. Spectral data of products: 2: 1H NMR (400 MHz, CDCl3): d
7.45 (m, 5H), 6.29 (t, 1H, J = 1.6 Hz), 2.41 (t, 2H, J = 6.8 Hz), 2.31 (m, 2H), 1.96 (m, 2H), 0.43 (s, 6H); 13C NMR (100 MHz, CDCl3): d 198.5,
165.9, 136.9, 135.6, 133.9, 129.6, 128.1, 38.1, 28.0, 23.5, ꢀ4.2; IR (neat) cmꢀ1: 3064, 3016, 2952, 2927, 2864, 1675, 1585, 1454, 1424, 1330,
1253; HRMS (MALDI, m/z) calcd. for C14H18OSiNa (M+Na)+: 253.1025, found 253.1017. 4: 1H NMR (400 MHz, CDCl3): d 7.42 (m, 5H), 2.40
(t, 2H, J = 6.8 Hz), 2.34 (m, 2H), 1.93 (m, 2H), 1.76 (t, 3H, J = 2.0 Hz), 0.45 (s, 6H); 13C NMR (100 MHz, CDCl3): d 198.7, 156.1, 143.8, 137.5,
133.6, 129.3, 128.0, 38.2, 31.0, 23.7, 16.0, ꢀ1.7; IR (neat) cmꢀ1: 3063, 3005, 2948, 2928, 2863, 1670, 1585, 1426, 1377, 1340, 1254; HRMS
(MALDI, m/z) calcd. for C15H20OSiNa (M+Na)+: 267.1181, found 267.1185. 6: 1H NMR (400 MHz, CDCl3): d 7.44 (m, 5H), 6.22 (s, 1H), 2.61
(m, 1H), 2.55 (m, 1H), 2.35 (m, 1H), 2.08 (m, 1H), 1.79 (m, 1H), 1.05 (d, 3H, J = 7.2 Hz), 0.47 (s, 3H), 0.46 (s, 3H); 13C NMR (100 MHz,
CDCl3): d 198.4, 170.4, 136.6, 136.2, 133.9, 129.6, 128.0, 33.9, 32.0, 30.7, 18.9, ꢀ2.9, ꢀ3.2; IR (neat) cmꢀ1: 3063, 2960, 2927, 2863, 1676,
1584, 1456, 1422, 1331, 1257; HRMS (MALDI, m/z) calcd. for C15H20OSiNa (M+Na)+: 267.1181, found 267.1172. 8: 1H NMR (400 MHz,
CDCl3): d 7.43 (m, 5H), 6.25 (s, 1H), 2.41 (m, 1H), 2.36 (m, 2H), 2.03 (m, 1H), 1.68 (m, 1H), 1.12 (d, 3H, J = 6.8 Hz), 0.43 (s, 6H); 13C NMR
(50 MHz, CDCl3): d 201.4, 164.7, 136.5, 134.2, 133.9, 133.7, 133.2, 129.6, 128.1, 41.6, 31.7, 27.8, 22.9, 15.1, ꢀ4.1, ꢀ4.2; IR (neat) cmꢀ1: 3051,
2957, 2925, 2856, 1676, 1588, 1456, 1427, 1374, 1253; HRMS (MALDI, m/z) calcd. for C15H20OSiNa (M+Na)+: 267.1181, found 267.1176. 10:
1H NMR (400 MHz, CDCl3): d 7.44 (m, 5H), 7.23 (m, 5H), 6.29 (t, 1H, J = 1.6 Hz), 3.34 (m, 1H), 2.52 (m, 2H), 2.37 (m, 1H), 2.21 (m, 1H), 1.93
(m, 1H), 1.58 (m, 1H), 0.42 (s, 6H); 13C NMR (50 MHz, CDCl3): d 199.7, 164.9, 140.0, 136.7, 135.6, 133.9, 129.7, 129.2, 128.3, 128.1, 128.0,
48.4, 35.3, 27.9, 27.7, ꢀ4.1, ꢀ4.2; IR (neat) cmꢀ1: 3062, 3023, 2923, 2856, 1953, 1887, 1816, 1672, 1596, 1494, 1451, 1426, 1339, 1253; HRMS
(MALDI, m/z) calcd. for C21H24OSi Na (M+Na)+: 343.1494, found 343.1496. 12: 1H NMR (400 MHz, CDCl3): d 7.44 (m, 5H), 6.26 (m, 1H),
5.76 (m, 1H), 5.03 (m, 2H), 2.61 (m, 1H), 2.41 (m, 1H), 2.32 (m, 2H), 2.08 (m, 2H), 1.66 (m, 1H), 0.43 (s, 6H); 13C NMR (100 MHz, CDCl3): d
199.9, 164.9, 136.6, 136.1, 135.6, 133.9, 129.6, 128.1, 116.7, 46.1, 33.7, 28.1, 27.6, ꢀ4.1, ꢀ4.2; IR (neat) cmꢀ1: 3070, 3012, 2923, 2857, 1674,
1587, 1427, 1339, 1255; HRMS (MALDI, m/z) calcd. for C17H22OSi Na (M+Na)+: 293.1338, found 293.1341. 14: 1H NMR (400 MHz, CDCl3):
d 7.45 (m, 5H), 0.43 (s, 6H), 6.19 (t, 1H, J = 2.0 Hz), 2.32 (m, 2H), 1.78 (t, 2H, J = 6.0 Hz), 1.09 (s, 6H); 13C NMR (50 MHz, CDCl3): d 203.6,
163.5, 135.8, 135.5, 133.9, 129.6, 128.1, 41.0, 37.0, 25.4, 24.1, ꢀ4.1; IR (neat) cmꢀ1: 3065, 3015, 2962, 2917, 1673, 1588, 1455, 1426, 1383,
1307, 1253; HRMS (MALDI, m/z) calcd. for C16H22OSiNa (M+Na)+: 281.1338, found 281.1336. 16: 1H NMR (400 MHz, CDCl3): d 7.45 (m,
5H), 6.39 (t, 1H, J = 2.0 Hz), 2.69 (m, 2H), 2.33 (m, 2H), 0.49 (s, 6H); 13C NMR (50 MHz, CDCl3): d 211.2, 182.4, 142.4, 135.2, 133.7, 129.7,
128.1, ꢀ35.0, 31.9, 3.9; IR (neat) cmꢀ1: 3052, 2957, 2921, 1708, 1430, 1252; HRMS (MALDI, m/z) calcd. for C13H16OSi Na (M+Na)+:
239.0868, found 239.0878.