Enantiomerically Pure Epoxychromans via Asymmetric Catalysis
摘要:
A practical and highly effective process for the asymmetric epoxidation of several 2,2-dimethylchromene derivatives is reported. Catalysis by Mn(salen) complex 4 in all cases affords epoxychromans with > 90% ee, and this method has been applied to the synthesis of two recently developed antihypertensive agents in enantiomerically pure form.