A facile synthesis of (S)-(-)-7,8-difluoro-3,4-dihydro-3-methyl-2H-1,4-benzoxazine by zinc chloride assisted Mitsunobu cyclization reaction

Abstract

A convenient procedure for preparation of the title compound of greater than or equal to 99% ee starting from 1-(2,3-difluoro-6-nitrophenoxy)-2-propanone (3) is presented. The key reaction is the intramolecular cyclization reaction in the presence of zinc chloride. Copyright (C) 1996 Elsevier Science Ltd