Tuning the Chemoselectivity of Silyl Protected Rhamnals by Temperature and Bronsted Acidity: Kinetically Controlled 1,2-Addition vs Thermodynamically Controlled Ferrier Rearrangement
Tuning the Chemoselectivity of Silyl Protected Rhamnals by Temperature and Bronsted Acidity: Kinetically Controlled 1,2-Addition vs Thermodynamically Controlled Ferrier Rearrangement
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通过温度和布朗斯台德酸度调节甲硅烷基保护的鼠李糖的化学选择性：动力学控制的 1,→2-→加成与热力学控制的 Ferrier 重排
DOI：
10.1021/acs.orglett.9b00009
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发表时间：
2019
期刊：
影响因子：
5.2
通讯作者：
Yonghai Chai
中科院分区：
文献类型：
--
作者：
Jincai Wang;Chuqiao Deng;Qi Zhang;Yonghai Chai
研究了甲硅烷基保护的鼠李醛与醇的化学选择性糖基化反应。在室温下，以（±）-CSA为催化剂，通过1，2-加成反应得到了动力学可控的2-脱氧鼠李糖苷。相比之下，当将反应温度升高至85 °C或使用CF 3SO 3 H代替时，仅通过Ferrier重排形成受控制的2，3-不饱和鼠李糖苷。这种可调的糖基化允许以优异的产率和高α-立体选择性容易和实用地获得2-脱氧和2，3-不饱和鼠李糖苷。
An acidity- and temperature-dependent chemoselective 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 allows facile and practical access to both 2-deoxyl and 2,3-unsaturated rhamnosides with excellent yields and high α-stereoselectivity.