By applying carbonyl compounds as sources of alkyl groups to the indium-catalyzed reductive alkylation of indoles,areliablea nd practical method capable of offering aw ide range of alkylindoles with structural diversity hasb een developed. An importantf eature of this method is that the loading of the indium catalyst can be reducedb y more than that of the original alkyne-based system.

Various functionalized indoles are alkylated with a diverse range of alkyl, aryl or hetaryl aldehydes or ketones following a practical and scalable one or two step procedure.