Rhodium-Catalyzed C2-Alkylation of Indoles with Cyclopropanols Using N,N-Dialkylcarbamoyl as a Traceless Directing Group

An efficient rhodium-catalyzed synthesis of C2-alkylated NH-free indoles has been achieved from substituted indoles and cyclopropanols. The reaction allows the synthesis of various C2-alkylated products in good to excellent yield. Important features of the method include the use of a N,N-dialkylcarbamoyl group as a traceless directing group, C-H/C-C bond functionalization, good functional group tolerance, broad scope, synthesis of pyrrolo[1,2-a]indole, and identification of potential intermediates.