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In the presence of a Cinchona alkaloid-based squaramide organocatalyst, the [3+2] cycloaddition of isatin-derived azomethine ylides with maleimides proceeded readily, thus delivering the desired pyrrolidine-fused spirooxindoles in 61-89% yields with >20:1 dr and 12 to >99 % ee. The absolute configuration of 5-chloro-1,5′-dimethyl-3′-phenyl-3′,3a′-dihydro-2′ H-spiro[indoline-3,1′-pyrrolo[3,4- c]pyrrole]-2,4′,6′(5′ H,6a′ H)-trione was unambiguously determined by means of X-ray single crystal structure analysis. The reaction mechanism was hypothesized to account for the enantioselective formation of 5-chloro-1,5′-dimethyl-3′-phenyl-3′,3a′-dihydro-2′ H-spiro[indoline-3,1′-pyrrolo[3,4- c]pyrrole]-2,4′,6′(5′ H,6a′ H)-trione. [ABSTRACT FROM AUTHOR]