Catalytic enantioselective synthesis of hydroxyimino tetrahydrobenzofuranones bearing trifluoromethylated quaternary stereocenter via tandem Michael addition/interrupted Nef reactions

Abstract

Tetrahydrobenzofuran derivatives are widely distributed in biologically active molecules and natural products. Herein, we reported an asymmetric tandem Michael addition/interrupted Nef reaction triggered by nitromethane directly as Michael donor catalyzed by chiral 2-aminobenzimidazole bifunctional organocatalyst. A series of enantiomerically enriched trifluoromethylated hydroxyimino tetrahydrobenzofuranones were synthesized in moderate to good isolated yields (up to 97 %) and enantioselectivities (up to 80 % ee).