Arylation and Aryne Insertion into C-Acylimines: A Simple, Flexible, and Divergent Synthesis of C2-Aryl Indoles.

We reveal a direct strategy for the flexible synthesis of C2-aryl/heteroaryl indoles without transition metal catalysts. The synthesis involves a one-pot, four-component reaction of readily available starting materials to offer diversity around the indole moiety with a broad substrate scope and high yields. The reaction proceeds via the Friedel-Crafts C-arylation of C-acylimine formed in situ , followed by N-arylation with aryne, a formal [3+2] cycloaddition, and a subsequent aromatization cascade.