在弱核友环境中由4-O-基团介导的β-l-Rhamnosylation和β-d-Mannosylation
Yongliang Zhang1, Changsheng Chen1, Yongtao Gao1
1National Glycoengineering Research Center and Shandong Key laboratory of Carbohydrate Chemistry and Glycobiology, Shandong University, 72 Binhai Rd Qingdao 266237, China.
Organic letters
|September 22, 2023
概括
这项研究展示了一种使用4-O-acyl组和弱协调性离子实现β-rhamnosylation和β-mannosylation的立体选择性糖化新方法. 2,3-欧托碳酸盐组促进了这一过程,并且可以很容易地去除.
科学领域:
- 碳水化合物化学 碳水化合物化学
- 有机合成 有机合成
- 立体选择性反应
背景情况:
- 在碳水化合物化学中,实现立体选择性糖化,特别是β-mannosylation和β-rhamnosylation,仍然是一个重大挑战.
- 现有的方法往往难以选择性,需要严苛的条件.
研究的目的:
- 开发一种高度立体选择性β-rhamnosylation和β-mannosylation的新策略.
- 调查4-O-基和弱协调离子在指导立体选择性中的作用.
- 建立一个简单的方法来去除指导性正碳酸盐组.
主要方法:
- 采用2,3-欧托碳酸盐保护组来指导立体化学.
- 使用碳或BARF (bis{2,4,4-trimethylpentyl) hydroborate) 离子来创建一个弱核友环境.
- 在优化条件下进行糖基化反应.
主要成果:
- 成功实现了β选择性拉姆诺基化和曼诺基化.
- 证明4-O-基组在指导β-选择性方面的关键作用.
- 证实了弱协调的离子会放大4-O-基团的指导作用.
- 通过使用1,3-propanediol和BF3·Et2O.O.实现的正碳酸盐组的去除.
结论:
- 开发的方法提供了一个有效的途径,以β-mannosides和β-rhamnosides.
- 4-O-方向和弱协调的离子的组合是实现高β选择性的关键.
- 正碳酸盐组作为一个有效和可移动的指导组.
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