Mannich-type addition o
f benzophenone imine glycinates across newly synthesized
N-(
p-toluenesul
fonyl)-chloroaldimines a
fforded -chloro-,-diamino ester derivatives with moderate diastereosel
ectivity asseparable mixtures o
f anti and
syn diastereomers. The -chloro-,-diamino esters were e
fficiently cyclizedunder basic conditions to the corresponding ,-aziridino -amino ester derivatives, representing a newclass o
f con
formationally constrained heterocyclic ,-diamino acid derivatives. The relative con
figurationo
f the aziridines was determined via X-ray di
ffraction analysis. M
echanisms and intermediate transitionstates to explain the stereochemical outcome o
f the Mannich reaction with di
fferent substrates or underdi
fferent conditions are proposed. The synthetic importance o
f the ,-aziridino -amino ester derivativesis demonstrated by their conversion into the corresponding Boc-prot
ected derivatives and ring openingreactions to ,-diamino esters and a -amino ,-unsaturated amino ester.
