Chen Chien-Tien, Weng Shiue-Shien, Kao Jun-Qi, Lin Chun-Cheng, Jan Mi-Dan
Department of Chemistry, National Taiwan Normal University, Academia Sinica, Taipei.
Org Lett. 2005 Jul 21;7(15):3343-6. doi: 10.1021/ol051178z.
[reaction: see text]. Aromatic aldehydes can be readily protected as acetals with 1,2- and 1,3-diols by using vanadyl triflate as a catalyst in CH(3)CN at ambient temperature. Carbohydrate-based 1,2- and 1,3-diols can similarly be protected in good to excellent yields. The catalyst can be readily recovered from the aqueous layer. In combination with vanadyl triflate-catalyzed sequential regioselective, reductive acetal opening and chemoselective acylations, the title method allows for differential functionalization of all four hydroxyl units in a given glucopyranoside.
[反应：见正文]。在室温下，以三氟甲磺酸氧钒为催化剂，在乙腈中，芳族醛可容易地与1,2 -二醇和1,3 -二醇反应生成缩醛而被保护起来。基于碳水化合物的1,2 -二醇和1,3 -二醇同样能以良好至优异的产率被保护起来。催化剂可很容易地从水层中回收。结合三氟甲磺酸氧钒催化的顺序区域选择性、还原性缩醛开环反应和化学选择性酰化反应，本方法能够对给定吡喃葡萄糖苷中的所有四个羟基单元进行差异化官能团化。
