Palladium-catalyzed intramolecular Heck dearomative gem-difluorovinylation of indoles

Chem Sci. 2022 Sep 13;13(39):11594-11599. doi: 10.1039/d2sc03169h. eCollection 2022 Oct 12.

Abstract

A palladium-catalyzed dearomative reaction of indoles has been developed through a domino Heck/gem-difluorovinylation sequence. By taking advantage of a difluorocarbene precursor (ClCF2COONa), the palladium difluorocarbene ([Pd][double bond, length as m-dash]CF2) 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.