General and efficient synthesis of indoles through triazene-directed c-h annulation

Abstract

Unprotected indoles are prepared with the title method, which has a wide scope for alkynes. Excellent regioselectivity was accomplished for aryl-alkyl and alkyl-alkyl disubstituted acetylenes. This reaction features an unusual 1,2 rhodium migration and ring-contraction-triggered N-N bond cleavage. It allows rapid conversion of the reaction products into several functional molecules. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.