Department of Chemistry , Indian Institute of Technology Patna , Bihta 801106 , Bihar , India.
Department of Chemistry , National Institute of Technology Patna , Patna 800005 , Bihar , India.
J Org Chem. 2019 Jan 18;84(2):589-605. doi: 10.1021/acs.joc.8b02422. Epub 2019 Jan 2.
An efficient and operationally simple gold(III)-catalyzed glycosylation protocol was developed using newly synthesized benchtop stable phenylpropiolate glycosyl (PPG) donors. Gold(III)-catalyzed activation of PPGs proceeds well with various carbohydrate and noncarbohydrate-based glycosyl acceptors and leads to their corresponding O/ N-glycosides in good to excellent yields with regeneration of reusable and easily separable phenylpropiolic acid. Differentially protected PPGs reacted well under the optimized reaction conditions. In particular, good anomeric selectivity was observed with mannosyl and rhamnosyl PPG donors. A preliminary mechanistic study reveals that the presence of a triple bond adjacent to the ester group is essential for activation, and PPG-based donor shows higher reactivity than analogous acetate and benzoate donors.
开发了一种使用新合成的苯并稳定苯丙炔酸糖基（PPG）供体的高效且操作简单的金（III）催化糖苷化方案。金（III）催化的 PPG 活化与各种碳水化合物和非碳水化合物的糖基受体很好地进行，导致相应的 O/N-糖苷以良好至优异的收率生成，同时可再生和易于分离的苯丙炔酸。在优化的反应条件下，受保护的 PPG 反应良好。特别是，甘露糖基和鼠李糖基 PPG 供体具有良好的端基选择性。初步的机理研究表明，酯基邻位的三键的存在对于活化是必不可少的，并且基于 PPG 的供体比类似的乙酸酯和苯甲酸酯供体具有更高的反应性。
