Enantioselective [4+2] Annulation to the Concise Synthesis of Chiral Dihydrocarbazoles
Haiyang Wang, Qingdong Hu, Mingxu Wang, Chang Guo
Abstract
A highly efficient phosphine-catalyzed enantioselective [4 + 2] annulation of allenoates with 3-nitroindoles or 3-nitrobenzothiophenes has been developed. The protocol represents a unique dearomatization-aromatization process to access functionalized dihydrocarbazoles or dihydrodibenzothiophenes with high optical purity (up to 97% ee) under mild reaction conditions. The synthetic utility of the highly enantioselective [4 + 2] annulation enables a concise synthesis of analgesic agent.
Topics & Concepts
Enantioselective synthesisAnnulationPhosphineChemistryAromatizationCombinatorial chemistryOrganic chemistryCatalysisStereochemistryAsymmetric Synthesis and CatalysisCatalytic C–H Functionalization MethodsAdvanced Synthetic Organic Chemistry