Palladium-Catalyzed Regioselective Monofluoroallylation of Indoles with -Difluorocyclopropanes.

We present a palladium-catalyzed ring-opening reaction that induces indoles to cross-couple with -difluorocyclopropanes. The reaction proceeds through a domino process of C-C bond activation and C-F bond elimination, followed by C-C(sp2) coupling to produce various 2-fluoroallylindoles. This method is characterized by its high functional group tolerance, good yields and high regioselectivity, under base-free conditions. The synthetic utility of the products is illustrated by the functionalization of the NH and C2 positions of the indole scaffold.