Practical synthesis of 1,1-difluoro-or 1-Fluoroalkenes from ,2,2-trifluoroacetophenone derivatives

Abstract

Since the discovery of the fact that compounds bearing a vinylic fluoride moiety often exhibit remarkable biological activities such as enzyme inhibitors, many synthetic methods for fluorine-substituted vinylic compounds have been developed. The synthesis of selectively fluorinated building blocks, such as arylsubstituted fluoro-Alkenes, also has become an area of interest in recent years. Herein we describe a novel and practical method for the synthesis of 1,1-difluoro-And 1-fluoroalkenes starting from easily accessible trifluoroacetophenone derivatives. Various 1,1-difluoro-And 1-fluoroalkenes were prepared by the reaction of the corresponding tosyl hydrazones that were derived from trifluoroacetophenone derivatives by treating with alkyl or aryllithium reagents via addition-elimination and single electron transfer (SET) mechanism.