Formation of 1H‐Aziridines from Chalcones and Hydroxylamine

Abstract Highly substituted chalcones 1 do not react with two molecules of hydroxylamine affording dioximes 2 or hydroxyamino‐oximes 3 as expected according to von Auwers' procedure: only one molecule of hydroxylamine is consumed leading to trans‐configurated 2‐benzoyl‐3‐phenyl‐1H‐aziridines 4.