Asymmetric Syntheses of (2<i>R</i>,3<i>S</i>)-3-Hydroxyproline and (2<i>S</i>,3<i>S</i>)-3-Hydroxyproline
作者:Stephen G. Davies、Ai M. Fletcher、Sean M. Linsdall、Paul M. Roberts、James E. Thomson
DOI:10.1021/acs.orglett.8b01736
日期:2018.7.6
Two synthetic routes have been developed for the asymmetric syntheses of (2R,3S)- and (2S,3S)-3-hydroxyproline. The key synthetic step in each of these strategies is the conversion of protected α,δ-dihydroxy-β-amino esters (either 2,3-anti- or 2,3-syn-configured) into β,δ-dihydroxy-α-amino esters (protected forms thereof), via the intermediacy of the corresponding aziridinium ions. The products of
已经开发出两种合成路线用于(2 R,3 S)-和(2 S,3 S)-3-羟基脯氨酸的不对称合成。所有这些策略中的关键合成步骤是将受保护的α,δ-二羟基-β-氨基酯(2,3-抗-或2,3- syn-构型)转化为β,δ-二羟基-α-氨基酯(其保护形式),通过相应的叠氮鎓离子的中间体。然后将这些立体特异性重排的产物环化并脱保护,得到(2 R,3 S)-3-羟基脯氨酸和(2 S,3 S)-3-羟基脯氨酸为单一非对映异构体(> 99:1 dr),总收率> 26%。