A family of the 3,6-branched Fuziα-glucans including the pentasaccharide repeating unit as well as its di-and trimers were efficiently achieved via a one-pot and convergent glycosylation strategy.All the protectedα-...A family of the 3,6-branched Fuziα-glucans including the pentasaccharide repeating unit as well as its di-and trimers were efficiently achieved via a one-pot and convergent glycosylation strategy.All the protectedα-glucans up to 15-mer were assembled with high yields and excellentα-stereoselectivity,which was secured by the synergisticα-directing effects of the Tol SCl/Ag OTf promotion system and the stericβ-facial shielding of bulky saccharide residues linked at the 6-O-position of glucosyl donors.Moreover,the 3,6-branched architecture of glycosyl donor was revealed to be more favorable for theα-selective glucosidation of primary hydroxyl group,especially in the case of large oligosaccharide acceptor.The structurally well-defined syntheticα-glucans would be useful for various biological studies.展开更多
Here we report a systematic investigation on the stereodirecting effects of a 4-O-ortho-cyanobenzyl ether(oBCN)group with a glucopyranosyi donor.Experimental studies revealed that the glycosylation reactions using thi...Here we report a systematic investigation on the stereodirecting effects of a 4-O-ortho-cyanobenzyl ether(oBCN)group with a glucopyranosyi donor.Experimental studies revealed that the glycosylation reactions using this donor generally show dual-stereoselectivities depending on the acceptor nucleophilicity,that is,glycosylation of weak nucleophile acceptors generally affordsα-glycosides specifically while glycosylation of strong nucleophile acceptors affords β-glycosides preferentially.展开更多
基金supported by the National Natural Science Foundation of China(No.22177060)the Young Scholars Program of Shandong University(No.2018WLJH41)+1 种基金the Open Projects Fund of Shandong Key Laboratory of Carbohydrate Chemistry and Glycobiology,Shandong University(No.2021CCG06)the Central Government Guide Local Science and Technology Development Funds(No.YDZX20203700002579)。
文摘A family of the 3,6-branched Fuziα-glucans including the pentasaccharide repeating unit as well as its di-and trimers were efficiently achieved via a one-pot and convergent glycosylation strategy.All the protectedα-glucans up to 15-mer were assembled with high yields and excellentα-stereoselectivity,which was secured by the synergisticα-directing effects of the Tol SCl/Ag OTf promotion system and the stericβ-facial shielding of bulky saccharide residues linked at the 6-O-position of glucosyl donors.Moreover,the 3,6-branched architecture of glycosyl donor was revealed to be more favorable for theα-selective glucosidation of primary hydroxyl group,especially in the case of large oligosaccharide acceptor.The structurally well-defined syntheticα-glucans would be useful for various biological studies.
基金This work was supported by the National Natural Science Foundation of China(22177060)the Young Scholars Program of Shandong University(2018WLJH41)the Central Government Guide Local Science and Technology Development Funds(No.YDZX20203700002579).
文摘Here we report a systematic investigation on the stereodirecting effects of a 4-O-ortho-cyanobenzyl ether(oBCN)group with a glucopyranosyi donor.Experimental studies revealed that the glycosylation reactions using this donor generally show dual-stereoselectivities depending on the acceptor nucleophilicity,that is,glycosylation of weak nucleophile acceptors generally affordsα-glycosides specifically while glycosylation of strong nucleophile acceptors affords β-glycosides preferentially.
