Palladium-catalyzed intramolecular Heck dearomative gem -difluorovinylation of indoles.

A palladium-catalyzed dearomative reaction of indoles has been developed through a domino Heck/ gem -difluorovinylation sequence. By taking advantage of a difluorocarbene precursor (ClCF 2 COONa), the palladium difluorocarbene ([Pd][double bond, length as m-dash]CF 2 ) species was formed smoothly. Then, a migratory insertion/β-H elimination process enabled access to polycyclic indolines containing 1,1-difluoroethylene units in acceptable yields with a broad substrate scope, which also showed dearomative gem -difluorovinylation for the first time. Remarkably, the superb diversified transformations allowed the product to install various functional groups.