The asymmetric synthesis of CF3-containing spiro[pyrrolidin-3,2′-oxindole] through the organocatalytic 1,3-dipolar cycloaddition reaction

Abstract

A new strategy for the construction of optically active 5′-CF₃ spiro[pyrrolidin-3,2′-oxindole] was described. A series of unprecedented 1,3-dipoles were obtained by condensation of CF₃CH₂NH₂ with isatins. The 1,3-dipolar cycloaddition reactions of these ketimines with enals gave the products bearing four contiguous stereogenic centers in excellent yields, diastereoselectivities and enantioselectivities.