Asymmetric substitution at the tetrasubstituted chiral carbon: Catalytic ring-opening alkylation of racemic 2,2-disubstituted aziridines with 3-substituted oxindoles

A highly diastereo- and enantioselective ring-opening alkylation of racemic 2,2-disubstituted aziridines with 3-substituted oxindoles is achieved under the catalysis of a chiral 1,2,3-triazolium salt. This reaction represents a hitherto unknown, catalytic stereoselective carbon-carbon bond formation through direct substitution at the tetrasubstituted chiral carbon.