Expedient C–H Chalcogenation of Indolines and Indoles by Positional-Selective Copper Catalysis

A versatile protocol for the C–H chalcogenation of indolines and indoles by means of copper catalysis was established. The C–H functionalization occurred selectively at the C7 position of indolines and exclusively at the C(2)–H bonds of indoles. The robust copper catalyst tolerated a wide range of functional groups and set the stage for the synthesis of diversely decorated indoles. Mechanistic studies were indicative of a SET-type mechanism and a facile C–H metalation being operative.