反应详情

To a solution of Compound 5 (2.58 g, 7.93 mmol) in DCM (50 mL) was slowly added BBr3 (8.5 mL, 8.5 mmol) at about −78° C. The resulting mixture was stirred overnight under argon while slowly warming up to room temperature. Methanol (60 mL) was added into the flask, and the mixture was stirred for about 3 hours. After concentration to 20 mL, the mixture was poured into DCM (200 mL), then washed with water, brine, and dried over Na2SO4, loaded on silica gel, and purified by flash column (hexanes/ethyl acetate 8:1 to 3:1). The desired fraction was concentrated to give a white solid (Compound 6) (1.84 g, in 77% yield).

1. customat about −78° C
2. stirringthe mixture was stirred for about 3 hours
3. concentrationAfter concentration to 20 mL
4. additionthe mixture was poured into DCM (200 mL)
5. washwashed with water, brine
6. dry with materialdried over Na2SO4
7. custompurified by flash column (hexanes/ethyl acetate 8:1 to 3:1)
8. concentrationThe desired fraction was concentrated