Reaction of Diazo Compounds with Difluorocarbene: An Efficient Approach towards 1,1-Difluoroolefins

A transition‐metal‐free difluoromethylenation of diazo compounds that proceeds under mild conditions has been developed and is based on the use of TMSCF2Br as the difluoromethylene source and tetrabutylammonium bromide (TBAB) as the promoter. The chemoselective formal carbene dimerization reaction is achieved owing to the electronic properties and the relative stability of the difluorocarbene intermediate. Formal carbene dimerization: The difluoromethylenation of diazo compounds was achieved under mild conditions with TMSCF2Br as the difluoromethylene source and tetrabutylammonium bromide (TBAB) as the initiator. The chemoselective formal carbene dimerization is achieved owing to the electronic properties and the relative stability of the difluorocarbene intermediate.