Starting from ethyl 2,4-dioxo-4-phenylbutyrate, both enantiomers of six enantiomerically pure a-hydroxy and a-amino acid esters (homophenylalanine derivatives) were prepared on >100 g scale. The key step involves a Pt-cinchona catalyzed enantioselective hydrogenation followed by enrichment via crystallization. All derivatives are commercially available.
从 2,4-二氧代-4-苯基丁酸乙酯开始,以 >100 g 的规模制备六种对映体纯的α-羟基和α-氨基酸酯(高苯丙氨酸衍生物)的两种对映异构体。关键步骤涉及 Pt-金鸡纳催化的对映选择性氢化,然后通过结晶富集。所有的衍生物都是可商购的。