Reaction Steps
By the same procedure used for the preparation of 2a, 180 mg (0.57 mmol) of the product of Example 5 gave 39 mg (22% yield) of compound 2b (column chromatography, hexane: ethyl acetate=2:1): [α]22D =-47.2° (c=1.925, CH2Cl2); IR (thin film) 3063, 2942, 2880, 2801, 1717, 1451, 1277, 1115, 939, 822, 712 cm-1 ; 1H NMR (CDCl3, 300 MHz) δ 7.97 (d, 2H, J=7.4 Hz), 7.55 (t, 1H, J=7.4 Hz), 7.43 (t, 1H, J=7.3 Hz), 6.42 (dd, 1H, J=13.4, 10.0 Hz), 5.93 (d, 1H, J=13.4 Hz), 5.19 (dt, 1H, J=11.4, 6.5 Hz), 3.30-3.20 (m, 1H), 3.15-3.05 (m, 1H), 2.85-2.75 (m, 1 H), 2.22 (s, 3H), 2.20-1.60 (m, 6H); 13C NMR (CDCl3, 75.46 MHz) δ166.0, 132.9, 130.4, 129.6, 128.4, 118.2, 68.6, 66.7, 61.4, 47.1, 41.3, 35.6, 26.1, 25.1; mass spectrum, m/z 307 (M+, 37Cl), 305 (M+, 35Cl), 270, 224, 184, 148, 105, 82, 77; HRMS calcd for C17H20NO235Cl (M+) 305.1178, found 305.1170.
