反应详情

To a stirred solution of compound (27) (35 g, 98.6 mmol) and thiocarbonate (11) (34.6 g, 148 mmol) in dichloromethane at 0° C. was dropwise added a 32% solution of peracetic acid (300 mmol) in acetic acid over 2 h. The reaction temperature was kept below 35° C. during the addition of peracetic acid. After the addition was complete, the reaction mixture was stirred overnight at room temperature. The resulting white precipitate was filtered and washed successively with water, and a mixture of ether and hexane (1:2), then dried under vacuum to afford the crude title compound. This product was crystallized once from a mixture of ethyl acetate and hexane (1:1) to afford the title compound (25) (13.7 g, 25% yield). The diastereomeric purity of the product was determined to be 98.4% d.e. by HPLC using a chiral column. 1H NMR (CDCl3, 400 MHz): δ 1.06 (d, 6H), 1.22 (d, 3H), 1.22 (d, 3H), 2.20 (m, 1H), 2.64 (hept. 1H), 6.01 (br. s, 2H), 6.64 (d, 1H), 7.47 (m, 4H), 7.63 (m, 2H), 8.07 (m, 4H).

1. additionAfter the addition
2. filtrationThe resulting white precipitate was filtered
3. washwashed successively with water
4. additiona mixture of ether and hexane (1:2)
5. customdried under vacuum
6. customto afford the crude title compound
7. customThis product was crystallized once from a mixture of ethyl acetate and hexane (1:1)