Access of cis-4-monofluoromethyl-1,3-oxazolidines via a formal [3+2] cycloaddition triggered by BF3 center dot OEt2

摘要

A series of cis-4-monofluoromethyl-1,3-oxazolidines were prepared from 2-monofluoromethyl-N-tosylaziridine and various aldehydes in the presence of (BF3OEt2)-O-center dot under mild conditions. The high regioselectivity of the reaction suggested that the electron-withdrawing ability of the monofluoromethyl group is similar to that of trifluoromethyl and difluoromethyl groups in this type of cycloaddition.