Synthesis of orthogonally protected 1,2-diaminopropanoic acids by ring-opening of 3-unsubstituted N-activated aziridine 2-carboxylates with para-methoxybenzylamine: a study of the regioselectivity of the reaction

Orthogonally protected 1,2-diaminopropanoic acids (DAPs) have been synthesised in good yields by the ring-opening of 3-unsubstituted N-activated aziridine 2-carboxylates with para-methoxybenzylamine. The choice of both the N-activating group and ester alkyl group had a significant influence on the ratio of attack at the α or β positions of the aziridine. However, the regiochemical outcome is not predictable.