Weak Chelating-Group-Directed Palladium-Catalyzed C-4 Arylation of Indoles.

A Pd(II)-catalyzed dehydrogenative remote C4-H coupling of indoles with unfunctionalized arenes at room temperature was reported. The weak chelating trifluoroacetyl group at the C3-position served as a directing group for the remote C4-H activation. Arenes with a wide range of substituents were employed as the coupling partner in the dehydrogenative cross-coupling reaction.