Assembly of Indolenines, 3-Amino Oxindoles, and Aldehydes into Indolenine-Substituted Spiro[pyrrolidin-2,3'-oxindoles] via 1,3-Dipolar Cycloaddition with Divergent Diastereoselectivities.

A novel one-pot 1,3-dipolar cycloaddition of indolenines, 3-aminooxindoles, and aldehydes is reported. The reaction provides indolenine-substituted spiro[pyrrolidin-2,3'-oxindoles] containing four contiguous stereogenic centers in high yields (up to 99%) and excellent diastereoselectivities (up to >20:1 dr) under mild conditions. Remarkably, the inversion of diastereoselectivity could be readily achieved through slightly modifying the reaction conditions.