How to obtain two optical antipodes of an octahydro-2H-pyrido [1,2-a] pyrazine starting from a single chiral synthon.

Abstract The synthesis of a (+)-(R,S)-2-aryl-4-methyl-3-oxo, octahydro-2H-pyrido [1,2-a]pyrazine and of its optical antipode (−)-(S,R)-2-aryl-4-methyl-3-oxo, octahydro-2H-pyrido[1,2-a]pyrazine, with a single synthetic sequence, and by making use of the natural ethyl lactate methansulfonate as the only chiral synthon, is described.