Construction of indolenine-substituted spiro[pyrrolidine-2,3′-oxindoles] from 2-alkenylindolenines and isatin-derived azomethine ylides.

An organic base-catalyzed 1,3-dipolar cycloaddition between 2-alkenylindolenines and azomethine ylides derived from isatins and benzylamines was successfully developed to assemble indolenine-substituted spiro [pyrrolidine-2,3′-oxindole] ring systems. Generally, good regioselectivities (up to 14:1 rr ) and high yields (up to 91%) were obtained under mild conditions. [ABSTRACT FROM AUTHOR]