An organocatalytic Michael-aldol cascade: formal [3+2] annulation to construct enantioenriched spirocyclic oxindole derivatives.

An efficient organocatalytic Michael-aldol cascade reaction for the asymmetric synthesis of spirocyclic oxindole derivatives fused with tetrahydrothiophenes has been developed through a formal [3+2] annulation strategy. This journal is © The Royal Society of Chemistry 2012