Transition-metal difluorocarbene complexes

Although transition metal carbenes have found widespread applications and difluorocarbene has served as a versatile intermediate, it is still quite challenging to make use of transition-metal difluorocarbenes in synthetic chemistry due to their unpredictable reactivities. In this Highlight, we review recent developments in the transition-metal-catalyzed or -mediated transfer of difluorocarbene and the reactivies and conversions of transition-metal difluorocarbene complexes. We start with the M=CF2 bonding, then provide the progress in the transfer of difluorocarbene, and finally briefly discuss the conversions of M=CF2 into other metal complexes. The understanding of the interesting reactivities of M=CF2 may help design the catalytic transfer of difluorocarbene for various reactions.