Activation of Oxaziridines by Lewis Acids:Application in Enantioselective Sulfoxidation

摘要

The preparation of new and easily accessible chiral N-alkyloxaziridines for asymmetric sulfides oxidation was investigated.Most significantly,we report here that inert iV-alkyloxaziridines can be activated by Lewis acids to achieve a fast,selective,and efficient oxygen atom transfer to sulfides.Asymmetric sulfoxidation by three new chiral oxaziridines(two of them were structurally characterized by X-ray analysis)afforded enantioselectivities ranging from 22% to 63% ee with the simplest aryl alkyl sulfides.