Enantioselective Preparation ofβ2-Amino Acids with Aspartate, Glutamate, Asparagine, and Glutamine Side Chains
作者:Gérald Lelais、Marino A. Campo、Sascha Kopp、Dieter Seebach
DOI:10.1002/hlca.200490142
日期:2004.6
(S)-β2-Homoamino acids with the side chains of Asp, Glu, Asn, and Gln have been prepared and suitably protected (N-Fmoc, CO2tBu, CONHTrt) for solid-phase peptide syntheses. The key steps of the syntheses are: N-acylation of 5,5-diphenyl-4-isopropyl-1,3-oxazolidin-2-one (DIOZ) with succinic and glutaric anhydrides (Scheme 2), alkylation of the corresponding Li-enolates with benzyl iodoacetate and Curtius
(小号) - β 2 -Homoamino酸与天冬氨酸,谷氨酸,天冬酰胺,谷氨酰胺和的侧链已被制备并适当保护的(Ñ -Fmoc,CO 2吨卜,CONHTrt),用于固相肽合成。的合成中的关键步骤是:Ñ 5,5-二苯基-4-异丙基-1,3-恶唑烷-2-酮(DIOZ)的酰化用琥珀和戊二酸酐(方案2),相应的对锂烷基化用碘代乙酸苄酯烯醇化和Curtius降解(方案4),并除去手性助剂(方案5)。此外,许多官能团操作(CO 2 H⇌CO 2吨卜,CO 2 Bn⇌CO 2 H,CbzNHFmocNH,CO 2 HCO 2 NH 2 CONHTrt; 为了达到四个目标结构,必须有方案2、4、5和6)。通过X射线晶体结构确定(方案2和图3)确认了构型分配。一个的对映体纯度β 2不是招和一个的β 2 hGln衍生物通过HPLC,在确定CHIRALCEL 1,分别为(:柱为99.7:0.3和> 99 4图。