An efficient synthesis of new 1′-C-methyl-α-O-disaccharides using 1-methylenesugars as the glycosyl donors
作者:Xiaoliu Li、Hiro Ohtake、Hideyo Takahashi、Shiro Ikegami
DOI:10.1016/s0040-4020(01)00319-2
日期:2001.5
A series of new 1′-C-methyl-α-disaccharides were firstly synthesized by the directly Lewis acid-catalyzed O-glycosidation of 1-methylenesugars used as glycosyl donors. The O-glycosidation afforded stereospecifically the corresponding 1′-methyl-α-O-glycosides whose configurations were tentatively assigned by the NMR spectra, COSY and the C–H coupling constant 3JH−2′,Me−1′. The O-glycosidation of the
首先通过直接路易斯酸催化用作糖基供体的1-亚甲基糖的O-糖基化反应,合成了一系列新的1' - C-甲基-α-二糖。所述Ô -glycosidation得到立体有择相应的1'-甲基α- ö -glycosides其构型暂时由NMR谱,COSY和C-H分配耦合常数3 Ĵ H-2'中,Me-1' 。乙酰基保护的1-亚甲基糖的O-糖基化表明C-2- O处的乙酰基 由于形成叔氧碳鎓离子作为稳定的中间体,因此通过邻近基团的参与,该位置不能有效地控制产物的立体化学。