Poulsen Lulu Teressa, Heuckendorff Mads, Jensen Henrik H
Department of Chemistry, Aarhus University, Langelandsgade 140, 8000 Aarhus C, Denmark.
ACS Omega. 2018 Jun 29;3(6):7117-7123. doi: 10.1021/acsomega.8b00880. eCollection 2018 Jun 30.
From a series of competition experiments, we have explored the degree to which various para-substituents (CN, Br, H, OMe, pyrrolidino) of a 2--benzoyl functionalized glucosyl donor of the thioglycoside type affect the rate of glycosylation under -iodosuccinimide/triflic acid activation. As expected, electron-withdrawing groups were found to decrease the rate of glycosylation, whereas electron-donating groups resulted in the opposite outcome, underscoring the influence on the reaction rate exerted by a participating group. On this basis, a Hammett linear free-energy relationship was established ( = 0.979, ρ = 0.6), offering fundamental insight into the magnitude of anchimeric assistance in glycosylation chemistry.
通过一系列竞争实验，我们探究了硫代糖苷型2-苯甲酰基官能化葡萄糖供体的各种对位取代基（CN、Br、H、OMe、吡咯烷基）在N-碘代琥珀酰亚胺/三氟甲磺酸活化下对糖基化速率的影响程度。正如预期的那样，吸电子基团会降低糖基化速率，而供电子基团则产生相反的结果，这突出了参与基团对反应速率的影响。在此基础上，建立了哈米特线性自由能关系（R² = 0.979，ρ = 0.6），为糖基化化学中邻基参与作用的程度提供了基本见解。
