Interplay of Protecting Groups and Side Chain Conformation in Glycopyranosides. Modulation of the Influence of Remote Substituents on Glycosylation?
作者:Suresh Dharuman、Harsha Amarasekara、David Crich
DOI:10.1021/acs.joc.8b01459
日期:2018.9.7
of glycosyl donors as a function of protecting group is discussed, raising the possibility that larger changes may be observed at the transition state for glycosylation. A comparable study with a series of ethyl 2,3,4-tri- O-benzyl-β-d-thioglucopyranosides reveals that no significant influence in side chain population is observed on changing the O6 protecting group.
一系列苯基2,3,6-三-O-苄基-β-d-硫代半乳糖和吡喃葡糖苷及其6 S-氘代异位异构体的合成和构象分析,其中4-位的保护基有系统性的变化位置,进行说明。对于吡喃半乳糖苷,将4-O-苄基醚替换为4-O-链烷酰基或芳酰基酯会导致侧链种群发生少量但可测量的位移,远离反式,构象构型,并有利于构式,反式构象剂。另一方面,在吡喃葡萄糖苷系列中,用4-O-链烷酰基或芳酰基酯代替4-O-苄基醚会导致反式,薄纱构象构象体的数量少量增加,但可测量的增加,但以薄纱结为代价。 ,gauche整合者。讨论了这些构象变化对糖基供体的异头反应性作为保护基的功能的众所周知的变化的可能调节作用,增加了在糖基化的过渡态观察到较大变化的可能性。用一系列乙基2,3,4-三-O-苄基-β-d-硫代吡喃葡萄糖苷进行的可比研究表明,未观察到侧链人口对改变O6保护基有重大影响。