Mannich-type addition of benzophenone imine glycinates across newly synthesized
N-(
p-toluenesulfonyl)-chloroaldimines afforded -chloro-,-diamino ester derivatives with moderate diastereoselectivity asseparable mixtures of
anti and
syn diastereomers. The -chloro-,-diamino esters were efficiently cyclizedunder basic conditions to the corresponding ,-aziridino -amino ester derivatives, representing a newclass of conformationally constrained heterocyclic ,-diamino acid derivatives. The relative configurationof the aziridines was determined via X-ray diffraction analysis. Mechanisms and intermediate transitionstates to explain the stereochemical outcome of the Mannich reaction with different substrates or underdifferent conditions are proposed. The synthetic importance of the ,-aziridino -amino ester derivativesis demonstrated by their conversion into the corresponding Boc-protected derivatives and ring openingreactions to ,-diamino esters and a -amino ,-unsaturated amino ester.