摘要
A highly practical asymmetric cpoxidation procedure for the synthesis of optically pure epoxychromans has been developed which employs 30% hydrogen peroxied as the oxidant and the Jacobsen-catalyst as the catalyst. The presence of imidazole has a significant effect on epoxidation rates and total turnovers. A variety of chromene derivatives were converted into corresponding epoxides of 89～100% ee in 72～92% isolated yields.
A highly practical asymmetric cpoxidation procedure for the synthesis of optically pure epoxychromans has been developed which employs 30% hydrogen peroxied as the oxidant and the Jacobsen-catalyst as the catalyst. The presence of imidazole has a significant effect on epoxidation rates and total turnovers. A variety of chromene derivatives were converted into corresponding epoxides of 89～100% ee in 72～92% isolated yields.
