Tanaka Hidenori, Ando Hiromune, Ishihara Hideharu, Koketsu Mamoru
Department of Chemistry, Faculty of Engineering, Gifu University, Gifu, Japan.
Carbohydr Res. 2008 Jul 21;343(10-11):1585-93. doi: 10.1016/j.carres.2008.05.005. Epub 2008 May 8.
A 5-N,7-O-carbonyl-protected sialyl donor was synthesized, and, unexpectedly, this donor showed beta-selectivity (alpha/beta = 1/2.4-1/20) on coupling with sugar acceptors in acetonitrile upon treatment with various promoter systems. For the coupling reaction in dichloromethane, a modified Ellervik's method (IBr and AgClO(4).H(2)O) was highly effective in activating the 5-N,7-O-carbonyl donor, providing moderate alpha-selectivity (alpha/beta = ~1.8/1).
合成了一种5-N,7-O-羰基保护的唾液酸供体，出乎意料的是，在用各种促进剂体系处理后，该供体在乙腈中与糖受体偶联时表现出β选择性（α/β = 1/2.4 - 1/20）。对于在二氯甲烷中的偶联反应，改良的埃勒维克方法（IBr和AgClO₄·H₂O）在活化5-N,7-O-羰基供体方面非常有效，提供了适度的α选择性（α/β = ~1.8/1）。
