Chiral aziridination of α,β-unsaturated esters and ketones using N-nitrenes in the presence of trifluoroacetic acid

Room temperature oxidations of the N-aminoquinazolone (1) in dichloromethane containing trifluoroacetic acid (TFA) in the presence of α,β-unsaturated esters or ketones gave aziridines with modest to high stereoselectivities; the presence of TFA allows these oxidations to be carried out at –60 °C with the expected improvement in selectivity and in the presence of ca. 1 mol. equiv. of alkene.