Novel Preparation of Chiral 3,2’-Pyrrolidinyl Spiro-oxindole from an Enantioselective Michael Addition between 3-(Diphenylmethylene)-amino-oxindole and Acrolein Catalyzed by a Cinchona Alkaloid

Abstract A new type of spiro[pyrrolinyl-3,2’-oxindole] scaffolds were effectively prepared from an enantioselective Michael/cyclization between a crucial synthon of 3-(diphenylmethylene)-amino oxindole and acrolein catalyzed by a cinchona alkaloid in up to 99% total yield with up to 99% ee. Those spiro-oxindole aldehyde imines were reduced to new kinds of prolineamide like spiro-oxindole chiral amine organocatalysts. The reaction has been successfully scaled up to a gram scale and most typical organocatalysts were further purified up to 99% ee by recrystallization in their hydrochloride salts.