Recent Advance in Defluorinative Transformations of α‐Trifluoromethyl Carbene Intermediates

ABSTRACT Over the past decade, the α‐trifluoromethyl metal carbene initiated defluorinative functionalization protocol has emerged as a robust and practical strategy for the incorporation of difluoromethylene motif. This review summarizes recent advances accomplished in gem ‐difluoroolefination and gem ‐difluoroalkylation based on β–F elimination via in situ‐generated α‐trifluoromethyl carbene intermediates, a field of research that has benefited from the utilization of readily available N ‐triftosylhydrazones or trifluoromethyl diazo compounds as fluorinated reagents. The content has been classified into four parts according to the different types of carbene transfer reactions, including coupling reaction and formal C‐H or X‐H insertion reactions for the gem ‐difluoroolefination; gem ‐difluoroalkylation and cycloaddition involving difluoroenol species. This article focuses on the mechanistic insights of the pivotal defluorination and functionalization processes, providing practical guidance for the rational design of innovative methodologies in fluorine chemistry. We hope that this method would offer a useful synthetic toolkit for the incorporation of difluoromethylene unit (‐CF 2 ‐) into a diverse array of functional molecules.