The combination of a boronic acid and a Lewis base, both employed in substoichiometric amounts, enables the regioselective silylation of cis-diol groups in alkylpyranoside substrates. The proposed mode of activation involves the formation of a tetracoordinate adduct that displays enhanced nucleophilicity at the boron-bound alkoxide groups.
将
硼酸和路易斯碱(两者的用量均为亚几何量)结合起来,可以对烷基
吡喃糖苷底物中的顺式二醇基团进行区域选择性
硅烷化。所提出的活化模式包括形成一种四配位加合物,该加合物在与
硼结合的氧化烷基上显示出更强的亲核性。