Cu(II)-NHC Catalyzed Insertion of Quinoid Carbenes into cis-Epoxides: Stereoselective Synthesis of trans-Dihydronaphthodioxine

A straightforward synthesis of trans-dihydronaphthodioxine has been efficiently accomplished through Cu­(II)-NHC catalysis, involving the stereoselective ring opening of cis-epoxides with quinoid-carbene. Intramolecular SN2-like substitution facilitates the inversion of stereochemistry during cis-epoxide ring opening. This reaction has been developed under simple conditions, demonstrating a broad substrate scope with a wide chemoselective profile. Additionally, late-stage functionalization of complex bioactive molecules has been successfully achieved.