Alternative procedure for the synthesis of enantiopure 1-benzoyl-2(S)-tert-butyl-3-methylperhydropyrimidin-4-one, a useful starting material for the enantioselective synthesis of α-substituted β-amino acids

Abstract

The title heterocycle is prepared in enantiomerically pure form and in 46-50% overall yield from (S)-asparagine, a readily available starting material. The synthetic route described in this report represents a major improvement over the original procedure (Tetrahedron: Asymmetry 1991, 3, 723), that afforded a 24-32% overall yield. Furthermore, the use of toxic reagents such as Pb(OAc)4 and dimethyl sulfate is avoided in the present protocol. © 2003 Published by Elsevier Science Ltd.