Asymmetric Catalytic Aziridination to Synthesize Spiro-aziridine Oxindoles.

Asymmetric catalytic aza-Michael-initiated ring closure of methyleneindolinones with N-tosyloxycarbamates has been established. The reaction using a chiral nickel complex catalyst enabled the formation of a series of spiro-aziridine oxindoles in good yields (up to 99 %) with high stereoselectivity (up to 97 % ee, >19 : 1 dr) under mild reaction conditions. Ring-opening of spiro-aziridine oxindole leads to formation of glycinate-bearing oxindoles with retention of configuration.