Concise synthesis of 3-deoxy-d-manno-oct-2-ulosonic acid (KDO) as a protected form based on a new transformation of α,β-unsaturated ester to α-oxocarboxylic acid ester via diol cyclic sulfite
作者:Atsuhito Kuboki、Toshihiro Tajimi、Yoshihide Tokuda、Dai-ichiro Kato、Takeshi Sugai、Susumu Ohira
DOI:10.1016/j.tetlet.2004.04.016
日期:2004.5
(overall 65% yield). The key step is the efficient transformation of readily available α,β-unsaturated ester to α-oxocarboxylic acid ester. The newly β-elimination of the corresponding diol cyclic sulfite and the in situ trap (DBU/TMSCl) into enol silyl ether was developed to give the tautomeric equivalent of α-oxocarboxylic acid ester. The deprotection of acid labile TMS ether provided the desired product
通过5个步骤(总收率65%)从2,3:5,6-二-O-异亚丙基-α-d-甘露呋喃糖(3)进行了KDO(1)的简明合成,作为适当保护的形式(2)。。关键步骤是将容易获得的α,β-不饱和酯有效转化为α-氧代羧酸酯。开发了新的β-消除相应的二醇环亚硫酸盐和原位捕集器(DBU / TMSCl)进入烯醇甲硅烷基醚的方法,得到了α-氧代羧酸酯的互变异构体当量。酸不稳定的TMS醚的脱保护提供了所需的产物。