Sweet Strain Release:Donor-Acceptor Cyclopropane Mediated Glycosylation  

作　　者：Xiong Xiao Han Ding Li-Cong Peng Xin-Yu Fang Yang-Yang Qin Qiu-Qi Mu Xue-Wei Liu 

机构地区：[1]School of Chemistry and Chemical Engineering,Northwestern Polytechnical University,Xi’an 710072 [2]School of Chemistry,Chemical Engineering and Biotechnology,Nanyang Technological University,Singapore 637371

出　　处：《CCS Chemistry》2023年第12期2910-2921,共12页中国化学会会刊（英文）

基　　金：the National Natural Science Foundation of China(grant no.22207092);the Natural Science Basic Research Plan of Shaanxi Province of China(grant no.2022JQ-091);the Fundamental Research Funds for the Central Universities(grant no.G2021KY05117)from China;the National Research Foundation(grant no.NRF-CRP22-2019-0002);the Ministry of Education(grant no.MOE-T2EP30120-0007);A*STAR(grant no.A20E5c0087)from Singapore for their financial support of this research.

摘　　要：Chemical glycosylation methodologies for the preparation of the bioactive oligosaccharides and glycoconjugates promise reliable access to these compounds as homogeneous materials with welldefined structures in sufficient amounts.Here we report a novel activation method of thio(seleno)glycosides employing donor-acceptor cyclopropane(DAC)agents and Sc(OTf)_(3).The Lewis acid catalyst converts DAC into a formal 1,3-zwitterionic species that in turn activates thioglycosides to furnish a glycosyl 1,4-zwitterionic intermediate,interconverting with reactive glycosyl oxocarbenium in the solution with reversible leaving-group dissociation.This activation method effectively promotes glycosylation reactions between both armed and disarmed thioglycosides and structurally diverse acceptors,affording oligosaccharides with satisfactory yields.The usefulness of our activation method has been demonstrated by the mechanism-inspired 2,4-dinitrobenzenesulfonyl(DNs)group directed S_(N)2-like glycosylation and the facile preparation of both linear and branched trisaccharides in one pot via controlled sequential activation of thioglycoside donors.

关 键 词：GLYCOSYLATION strain release donor-acceptor cyclopropane glycosyl zwitterion onepot glycosylation 

分 类 号：O62[理学—有机化学]