Kovác P, Yeh H J, Glaudemans C P
NIDDK, National Institutes of Health, Bethesda, MD 20892.
Carbohydr Res. 1987 Nov 15;169:23-34. doi: 10.1016/0008-6215(87)80239-2.
Methyl 3-deoxy-3-fluoro-alpha- and beta-D-glucopyranosides and alpha- and beta-D-glucofuranosides were prepared by methanolysis of 3-deoxy-3-fluoro-1,2:5,6-di-O-isopropylidene-alpha-D-glucofuranose. Crystalline 3,4,6-tri-O-acetyl-2-deoxy-2-fluoro-alpha-D-glucopyranosyl chloride (2) and the corresponding glycosyl bromide (3) were prepared from 1,3,4,6-tetra-O-acetyl-2-deoxy-2-fluoro-beta-D-glucopyranose (1). Reaction of 2 with methanol under the conditions of both silver triflate- and silver perchlorate-catalyzed glycosylation showed remarkable lack of stereoselectivity for the formation of the corresponding methyl alpha-glycoside, despite the presence at C-2 of the fluorine functionality presumably not capable of neighboring-group participation. Pure methyl 2-deoxy-2-fluoro-alpha- and beta-D-glucopyranosides were obtained by fractional crystallization from the mixture formed by methanolysis of 1. The structure of these substances as well as of several other derivatives of 2-deoxy-2-fluoro- and 3-deoxy-3-fluoro-D-glucose were verified by n.m.r. (1H, 13C, and 19F) spectroscopy.
通过3-脱氧-3-氟-1,2:5,6-二-O-异亚丙基-α-D-呋喃葡萄糖的甲醇解反应制备了3-脱氧-3-氟-α-和β-D-吡喃葡萄糖苷以及α-和β-D-呋喃葡萄糖苷。由1,3,4,6-四-O-乙酰基-2-脱氧-2-氟-β-D-吡喃葡萄糖（1）制备了结晶性的3,4,6-三-O-乙酰基-2-脱氧-2-氟-α-D-吡喃葡萄糖基氯（2）和相应的糖基溴（3）。在三氟甲磺酸银和高氯酸银催化的糖基化条件下，2与甲醇反应时，尽管在C-2位存在可能无法参与邻基参与的氟官能团，但对于相应的甲基α-糖苷的形成却表现出明显的立体选择性不足。通过对1甲醇解形成的混合物进行分步结晶，得到了纯的2-脱氧-2-氟-α-和β-D-吡喃葡萄糖苷。这些物质以及2-脱氧-2-氟-和3-脱氧-3-氟-D-葡萄糖的其他几种衍生物的结构通过核磁共振（1H、13C和19F）光谱进行了验证。
