(Aka) to quantify the nucleophilicity of hydroxyl groups in glycosylation influenced by the steric, electronic and structural effects, providing a connection between experiments and computer algorithms. The subtle reactivity differences among the hydroxyl groups on various carbohydrate molecules can be defined by Aka, which is easily accessible by a simple and convenient automation system to assure
Halogen-bond-assisted radical activation of glycosyl donors enables mild and stereoconvergent 1,2-cis-glycosylation
作者:Chen Zhang、Hao Zuo、Ga Young Lee、Yike Zou、Qiu-Di Dang、K. N. Houk、Dawen Niu
DOI:10.1038/s41557-022-00918-z
日期:2022.6
2-cis-glycosylation without using metals, strong (Lewis) acids, elaborate catalysts or labile substrates. Our method operates by a unique mechanism: it activates glycosyl donors through a radical cascade rather than the conventional acid-promoted, ionic process. As elucidated by computational and experimental studies, the allyl glycosyl sulfones (as donors) form halogen bond complexes with perfluoroalkyl iodides, which—merely
Highly Stereoselective Glycosyl-Chloride-Mediated Synthesis of 2-Deoxyglucosides
作者:Ved Prakash Verma、Cheng-Chung Wang
DOI:10.1002/chem.201203418
日期:2013.1.14
Cl intermediates: The glycosylation of per-O-benzylated 2-deoxy- and 2,6-dideoxythioglycosides, promoted by the combination of para-toluenesulfenyl chloride (p-TolSCl) and silver triflate (AgOTf), furnished the products in high yields and high stereoselectivity. The glycosyl chloride was the intermediate (see scheme).