Asymmetric Synthesis of Chiral α‐CF2H spiro[indoline‐3,3'‐thiophene] via Phase‐Transfer Catalyzed Sulfa‐Michael/Michael Domino Reaction

Abstract. An efficient and practical sulfa-Michael/Michael domino reaction of (E)-4-mercapto-2-butenoates with difluoromethyl-eneoxindoles by catalyzed a quinidine-derived ammonium salts as phase transfer catalyst has been disclosed. Under mild conditions, a broad range of CF2H- containing spiro[indoline-3,3'-thiophene]s catalysed by only 5 mol% PTC catalyst, bearing three adjacent chiral centers including two vicinal spiro quaternary stereocenters, were obtained in high yields (up to 98%) with excellent diastereoselectivities (> 20:1 dr, in all cases) and high enantioselectivities (up to 98% ee) in short reaction times (almost less than 20 minutes). Keywords: Phase-Transfer Catalyst; CF2H; spiro[indoline-3,3'-thiophene]s; vicinal quaternary stereocenters; Sulfa-Michael/Michael domino reaction

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