Enantiospecific synthesis of 3,4-disubstituted glutamic acids via controlled stepwise ring-opening of 2,3-aziridino-γ-lactone

The preparation of enantiomerically pure 3,4-disubstituted glutamic acids is described starting from d-ribose. This preparation involved the use of a 2,3-aziridino-γ-lactone whose reactivity towards nucleophiles could be efficiently controlled to allow selective functionalization at the β-position. A key step of the strategy was a titanate-mediated transesterification of a dimethyl ester into a dibenzyl analogue, allowing efficient deprotection to the free amino acid by hydrogenolysis.