Redox-Neutral Rhodium(III)-Catalyzed Chemospecific and Regiospecific [4+1] Annulation between Indoles and Alkenes for the Synthesis of Functionalized Imidazo[1,5-<i>a</i>]indoles
Fei Zhao, Qiao Jin, Yangbin Lu, Xiaoning Zhang, Long Dai, Siyu Liu, Hangcheng Ni, Xiuwen Jia, Xiaowei Wu, Shiyao Lu
Abstract
Exploiting internal alkenes embedded with an oxidizing function/leaving group as a rare and unconventional one-carbon unit, a redox-neutral rhodium(III)-catalyzed chemo- and regiospecific [4+1] annulation between indoles and alkenes for the synthesis of functionalized imidazo[1,5-a]indoles has been achieved. Internal alkenes employed here can fulfill an unusual [4+1] annulation rather than normal [4+2] annulation/C–H alkenylation. This method is characterized by excellent chemo- and regioselectivity, broad substrate scope, good functional group tolerance, good to high yields, and redox-neutral conditions.
Topics & Concepts
AnnulationChemistryOxidizing agentRhodiumRegioselectivityCatalysisRedoxFunctional groupCombinatorial chemistryOrganic chemistryMedicinal chemistryPolymerCatalytic C–H Functionalization MethodsCatalytic Cross-Coupling ReactionsCatalytic Alkyne Reactions