3-Amino Oxindole Schiff Base as Synthon for Enantioselective Preparation of Spiro[oxindol-3,2'-pyrrol] from a Michael/Cyclization Reaction Catalyzed by a Bifunctional Cinchona.

A new and crucial synthon of 3-((diphenylmethylene)-amino)-oxindole was designed and synthesized, for which an organocatalytic and enantioselective Michael/cyclization reaction with a terminal vinyl ketone catalyzed by a cinchona base was disclosed. A wide variety (28 examples) of almost all new chiral spiro[oxindol-3,2'-pyrrols] were prepared in excellent yields (up to 99%) with excellent enantioselectivities (95-99% ee), of which a typical chiral spiro product was further reduced to chiral spiro[oxindole-3,2'-pyrrolidine].