Asymmetric Synthesis of Spirooxindoles

Significance

Wang and co-workers report the enantioselective synthesis of densely functionalized 3,3′-thiopyrrolidonyl spirooxindoles having three contiguous stereogenic centers. This reaction combines α-isothiocyanatoimides, methyl­eneindolinone derivatives and a rosin-derived tertiary amine thiourea as catalyst and proceeds through a Michael-cyclization sequence. The products are obtained with good yield, diastereo­selectivity, and enantioselectivity.