Borane- and Silylium-Catalyzed Difunctionalization of Carbohydrates: 3,6-Anhydrosugar Enabled 1,6-Site Selectivity
作者:Joshua J. Clarke、Kevin Basemann、Neyen Romano、Stephen J. Lee、Michel R. Gagné
DOI:10.1021/acs.orglett.2c01243
日期:2022.6.17
A novel diastereoselective, Lewis acid catalyzed 1,6-difunctionalization of galactose and mannose derivatives has been developed in one pot, via sequential nucleophile additions. Our studies point to the formation of a 3,6-anhydrosugar intermediate as key to the 1,6-site-selectivity. Starting material-specific reactivity occurs when competitive ring-opening C–O cleavage is possible, owed to basicity
一种新型的非对映选择性路易斯酸催化的半乳糖和甘露糖衍生物的 1,6-双官能化已经通过连续的亲核试剂加成在一个锅中开发出来。我们的研究指出 3,6-脱水糖中间体的形成是 1,6 位点选择性的关键。由于碱度和立体电子稳定性的差异,当竞争性开环 C-O 裂解成为可能时,就会发生起始材料特异性反应。最后,Mayr 亲核性参数值有助于预测哪些反应条件最适合特定的亲核试剂。