The formation of a crystalline oxazolidin-5-one from (L)-alanine and its use as a chiral template in the practical synthesis of α-substituted alanine esters

Abstract

Three different protocols to synthesize oxazolidin-5-ones have been studied with the goal to develop a method to synthesize a diastereomerically pure oxazolidin-5-one. A novel method is reported that uses a dynamic crystallization-induced asymmetric transformation to isolate a single diastereomer of an oxazolidin-5-one in 92% yield on kilogram scale. Alkylation of the oxazolidin-5-one template leads to good-to-excellent yields of N-protected α-substituted alanine esters in >98-99% ee. © Schweizerische Chemische Gesellschaft.