Configurational Assignment of ‘Cryptochiral’ 10-Hydroxystearic Acid Through an Asymmetric Catalytic Synthesis
作者:Andreas Brunner、Lukas Hintermann
DOI:10.1002/hlca.201600242
日期:2016.12
An asymmetric catalytic total synthesis of (S)‐10‐hydroxystearic acid (1) for comparison of its absolute configuration to that of samples obtained by fermentative hydration of oleic acid is reported. The synthesis involves two catalytic key‐steps, namely Ru‐catalyzed anti‐Markovnikov hydration of 9‐decynoic acid (7) to 10‐oxodecanoic acid (5), followed by titanium‐mediated asymmetric catalytic addition
报道了(S)-10-羟基硬脂酸(1)的不对称催化全合成,用于比较其绝对构型与通过油酸发酵水合获得的样品的绝对构型。合成涉及两个催化关键步骤,即Ru催化的9-癸癸酸(7)到10-氧代十二烷酸(5)的反马尔科夫尼科夫水合,然后是钛介导的不对称催化的二辛基锌(25)到5 in手性配体N,N' -(((1 R,2 R)-环己烷-1,2-二基)双(1,1,1-三氟甲磺酰胺)的存在(6)。合成是短而有效的,并且避免使用保护基。将10-十一碳烯酸(9)臭氧分解为5可以为合成路线提供一个替代的入口点。以10,11-二溴代正癸酸(11)为模型底物,并使用qNMR定量分析所有反应产物,研究了在各种条件下(ω,ω -1)-二溴链烷酸向ω-链烷酸的双脱氢溴化反应。本文介绍的合成方法有可能被推广到各种n-羟基脂肪酸的不对称催化合成中。