Rhodium(III)- and iridium(III)-catalyzed C7 alkylation of indolines with diazo compounds.

A Rh(III)-catalyzed procedure for the C7-selective C-H alkylation of various indolines with α-diazo compounds at room temperature is reported. The advantages of this process are: 1) simple, mild, and pH-neutral reaction conditions, 2) broad substrate scope, 3) complete regioselectivity, 4) no need for an external oxidant, and 5) N2 as the sole byproduct. Furthermore, alkylation and bis-alkylation of carbazoles at the C1 and C8 positions have also been developed. More significantly, for the first time, a successful Ir(III)-catalyzed intermolecular insertion of arene C-H bonds into α-diazo compounds is reported.