Divergent synthesis of 4-amino indoles with free amine groups via tandem reaction of 2-alkynylanilines

A process for the divergent synthesis of a variety of 4-amino indoles having N1 or C4 free amine groups was reported. This process involves an oxidative dearomatization, an imine exchange, a cascade 1,4-addition/cyclization/aromatization, and a selective deprotection. The formed 4-amino indoles can be converted to 4,7-difunctionalized indoles via selective Friedel-Crafts alkylation.