Pletcher Joseph M, McDonald Frank E
Department of Chemistry, Emory University, Atlanta, Georgia 30322, USA.
Org Lett. 2005 Oct 13;7(21):4749-52. doi: 10.1021/ol051971s.
[reaction: see text] Schmidt glycosylation of the appropriately protected 3,4-dihydroxycinnamate methyl ester with 2,3,4-triacetoxyfucopyranosyltrichloroacetimidate gives aryl glycoside in high yield and diastereoselectivity. 2-Sulfation of fucose, installation of taurine, and global deprotection of the remaining protecting groups affords the fucose-aglycon conjugate of saccharomicin. This synthesis which arises from L-fucose also establishes the absolute configuration of the reducing terminus of the saccharomicin oligosaccharide.
[反应:见正文] 用2,3,4-三乙酰氧基岩藻糖基三氯乙酰亚胺酯对适当保护的3,4-二羟基肉桂酸甲酯进行施密特糖基化反应,可高产率和非对映选择性地得到芳基糖苷。对岩藻糖进行2-O-硫酸化、引入牛磺酸,并对其余保护基团进行整体脱保护,得到了糖霉素的岩藻糖-苷元缀合物。这种由L-岩藻糖出发的合成方法也确定了糖霉素寡糖还原端的绝对构型。