Oxidative N-Heterocyclic Carbene-Catalyzed [gamma]-Carbon Addition of Enals to Imines: Mechanistic Studies and Access to Antimicrobial Compounds

The reaction mechanism of the [gamma]-carbon addition of enal to imine under oxidative N-heterocyclic carbene catalysis is studied experimentally. The oxidation, [gamma]-carbon deprotonation, and nucleophilic addition of [gamma]-carbon to imine were found to be facile steps. The results of our study also provide highly enantioselective access to tricyclic sulfonyl amides that exhibit interesting antimicrobial activities against X. oryzae, a bacterium that causes bacterial disease in rice growing.