Synthesis of Indole-Fused Oxepines via C–H Activation Initiated Diastereoselective [5 + 2] Annulation of Indoles with 1,6-Enynes
Xiaoli Huang, Yan Shi, Yongzhuang Wang, Jiao Jiao, Yuhai Tang, Jing Li, Silong Xu, Yang Li
Abstract
A rhodium-catalyzed diastereoselective formal [5 + 2] annulation of indoles with cyclohexadienone-containing 1,6-enynes has been established via indole 2,3-difunctionalization. The reaction, probably proceeding through tandem indole C2–H alkenylation and intramolecular Friedel–Crafts alkylation relay, provides rapid construction of indole-fused oxepines in good to excellent yields with a broad substrate scope. This method also features concomitant construction of cis-hydrobenzo[b] oxepine scaffolds, a core unit found in numerous natural products of important biological activities.
Topics & Concepts
Indole testAnnulationChemistryIntramolecular forceAlkylationCombinatorial chemistryStereochemistrySubstrate (aquarium)CatalysisOrganic chemistryGeologyOceanographyCatalytic C–H Functionalization MethodsSynthesis and Catalytic ReactionsCyclopropane Reaction Mechanisms