A chiral relay auxiliary for the synthesis of homochiral α-amino acids

Abstract

A new chiral auxiliary (3S)-N,N′-bis(p-methoxybenzyl)-3-isopropylpiperazine-2,5-dione 7 has been developed for the asymmetric synthesis of α-amino acids. The auxiliary 7 employs a novel chiral relay network based on non-stereogenic N-benzyl protecting groups which enhance the diastereoselectivity observed during alkylation of its C₆ enolate 25.