氧化银(Ⅰ)在糖羟基上选择性对-甲基苯磺酰化中的应用

Silver（Ⅰ） oxide was applied to the selective p-tosylation of hydroxyls of saccharide. The reaction of p-methylphenyl-4,6-O-benzylidene-1-thio-β-D-glucopyranoside（A） with a stoichiometric amount of p-toluenesulfonyl chloride（TsCl） in the presence of silver（Ⅰ） oxide and a catalytic amount of potassium iodide selectively led to the monotosylate derivative:p-methylphenyl 3-O-p-toluenesulfonyl-4,6-O-benzylidene-1-thio-β-D-glucopyranoside（B） in a high yield（97%）. A possible mechanism of the reaction is proposed. The rational reaction process is that at n（TsCl）∶n（Ag2O）∶n（A）∶n（KI）=1.2∶1.5∶1.0∶0.2, the mixture is stirred at room temperature for 8 h, 2.74 g（97%）B could be isolated from 2.0 g of compound A.