反应详情

A solution of 5-(propene-3-yl)cyclopent-2-enone (4.28 g, 35 mmol) in dichloromethane (15 mL) was treated with benzyl carbamate (10.6 g, 70 mmol) and bismuth trinitrate pentahydrate (2.2 g, 4.5 mmol), stirred rapidly for 18 h, then diluted with dichloromethane (50 mL). The mixture was filtered through Celite® (rinse with dichloromethane) and the filtrate added directly to a silica gel column (˜550 cc). Elution first with 3:2 petroleum ether/dichloromethane afforded recovered starting material (1.01 g), then 4:1 heptane/ethyl acetate gave the subject compound (4.54 g, 47.5% uncorrected yield) as a pale yellow oil. NMR (CDCl3): δ 7.28 (br s, 5 H), 5.55-5.70 (m, 1 H), 5.03 (br s, 2 H), 4.90-5.10 (m, 2 H), 4.75-4.90 (m, 1 H), 4.10-4.30 (m, 1 H), 2.40-2.80 (m, 2 H), 2.15-2.40 (m, 2 H), 1.85-2.15 (m, 3 H). MS (M+Na): 296.0; MS (M−H2O+1): 256.0 (no M+1 visible).

1. filtrationThe mixture was filtered through Celite® (rinse with dichloromethane)
2. additionthe filtrate added directly to a silica gel column (˜550 cc)
3. washElution first with 3:2 petroleum ether/dichloromethane
4. customafforded
5. customrecovered
6. custom4:1 heptane/ethyl acetate gave
7. customthe subject compound (4.54 g, 47.5% uncorrected yield) as a pale yellow oil