反应详情

The procedure as described above in connection with Intermediate 1 was repeated to prepare ethyl 2,3-dibromo-4-(3,4-dimethoxyphenyl)-4-oxobutanoate (7.3 g, 95%) in the form of a diastereo mixture as a colorless foam (mixing ratio=63:37) from, a solution of ethyl 4-(3,4-dimethoxyphenyl)-4-oxo-2-butenoate (4.8 g, 18 mmol) in methylene chloride (500 ml) and a solution of bromine (1.1 ml) in methylene chloride (100 ml). The diastereo mixture was used in the next reaction without separation.

1. customThe diastereo mixture was used in the next reaction without separation