glycosylation of silyl-protected rhamnals with alcohols has been revealed. The reaction undergoes a 1,2-addition pathway with (±)-CSA as the catalyst at rt, affording kinetically controlled 2-deoxyl rhamnosides. In contrast, only thermodynamically controlled 2,3-unsaturated rhamnosides are formed via Ferrier rearrangement when elevating reaction temperature to 85 °C or using CF3SO3H instead. This tunable glycosylation
已经揭示了醇对甲
硅烷基保护的鼠类的酸度和温度依赖性的
化学选择性糖基化作用。该反应在室温下以(±)-CSA作为催化剂经历1,2-加成途径,得到动力学控制的2-脱氧
鼠李糖苷。相反,当将反应温度提高到85°C或使用CF 3 SO 3 H时,通过Ferrier重排仅形成热力学控制的2,3-不饱和
鼠李糖苷。这种可调节的糖基化可以轻松,实用地获得2-脱氧和2,3-不饱和
鼠李糖苷,并具有出色的收率和高α-立体选择性。