Diastereoselective synthesis of syn,syn- and syn,anti-2,4-diamino-3- hydroxyglutaric acid derivatives from ethyl α-acyl alaninates

Article abstract of DOI:10.1016/S0040-4020(99)00065-4

Syn,syn- and syn,anti-isomers of the four possible diastereomers of O,N,N'-protected 2,4-diamino-3-hydroxyglutaric acid derivatives 3-7 were diastereoselectively obtained. Syn,syn isomers of oxazolines 3 were selectively achieved by an aldol-like reaction in protic conditions between α-metallated ethyl isocyanoacetate 1 and α-acyl alaninates 2. Derivatives 4 with a syn,anti-configuration were obtained under epimerization reaction conditions, whereas derivatives 5-7 with a syn,syn-configuration were selectively obtained under kinetic reaction conditions.