Linear dependence of the glycosylation stereoselectivity ofO-trityl ethers by carbohydrate 1,2-O-cyanoalkylidene derivatives on anion concentrations. Effect of substituents in the glycosyl acceptor and a new mechanism of 1,2-cis-glycosides formation
Tóm tắt
The dependence of the stereochemical outcome of trityl-cyanoalkylidene condensation (α/β-ratio of disaccharides) on the concentration of a catalyst (TrClO4) was studied. The dependence was shown to be linear over a wide range of concentrations of the catalyst. The mechanism of the reaction and the effect of the nature of protective groups in the glycosyl acceptor on the stereochemistry of glycosylation are discussed. A new mechanism of 1,2-cis-glycosides formation is proposed.
Tài liệu tham khảo
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