Synthesis of Spirooxindoles by Catalytic Tandem Reaction of 2-Arylidene-1,3-indanediones with 2-(2-Oxoindolin-3-yl)malononitriles

Abstract

A facile synthetic method has been developed for the synthesis of spirooxindoles bearing benzofuran-1(3H)-one. The Michael addition-triggered tandem cyclization reaction between 2-arylene-1,3-indanediones with 2-(2-oxoindolin-3-yl)malononitriles catalyzed by K2CO3 affording the spirooxindole products bearing a 3-oxoisobenzofuran-1(3H)-ylidene motif in good to high yields (up to 95%) with excellent diastereoselectivity (up to >20:1 dr). Meanwhile, the gram-scale preparation verifies the practicality of this reaction.