Synthesis of AsymmetricN-Arylaziridine Derivatives Using a New Chiral Phase-Transfer Catalyst

Substituted N-arylaziridine derivatives were synthesized in an enantioselective manner from N-acyl-N-arylhydroxylamine and electron deficient olefins using chiral phase-transfer catalysts (CPTCs) derived from cinchona alkaloids. The structures of the CPTCs were ascertained through various spectral techniques such as FT-IR, 1H NMR, 13C NMR, and mass spectroscopy, as well as elemental analyses. The efficiency and chiral behavior of a range of CPTCs were studied with respect to both yield and ee. The chemical yields were in the range of 24-92% and ee was 29-95%. It was observed that the S-enantiomers were more predominant than the R-enantiomers with cinchonidine as catalyst; whereas the R-enantio­mers were more predominant in the case of cinchonine based CPTC. We propose here a suitable mechanism for the formation of chiral aziridines as well as optimized procedures for a range of N-arylaziridine derivatives.