1,3,4,6-Tetra-O-acetyl-2-chloroacetamido-2-deoxy-β-d-glucopyranose as a glycosyl donor in syntheses of oligosaccharides
作者:Falguni Dasgupta、Laurens Anderson
DOI:10.1016/0008-6215(90)84083-7
日期:1990.7
beta-linked disaccharides were obtained from the galactoside and glucoside acceptors, but with allyl 2-acetamido-3,6-di-O-benzyl-2-deoxy-alpha-D-glucopyranoside, stereoselectivity was lost (alpha:beta-ratio 1:2). Allyl and benzyl 2-acetamido-3,6-di-O-benzyl-2-deoxy-beta-D-glucopyranosides gave, respectively, the allyl and benzyl beta-glycosides of the donor as major products. A mechanism is proposed for this
测试了1,3,4,6-四-O-乙酰基-2-氯乙酰氨基-2-脱氧-β-D-吡喃葡糖作为经由氯化铁催化的偶联反应寡糖合成的糖基供体。尝试的糖基受体(总共6个)是分别在3和4位具有游离OH基的O-苄基保护的D-半乳糖苷,以及类似取代的D-葡萄糖和2-乙酰氨基-2-脱氧-D-葡萄糖的未取代糖苷在O-4上 在4种情况下,通过利用Garegg和Hultberg的氰基硼氢化物方法将4,6-O-亚苄基---- 6-O-苄基[Carbohydr。Res.93(1981)c10-c11; 108(1982)97-101]。从半乳糖苷和葡萄糖苷受体获得了良好或优异的β联结二糖收率,但是使用了2-acetamido-3烯丙基,6-二-O-苄基-2-脱氧-α-D-吡喃葡萄糖苷,失去了立体选择性(α:β-比率1:2)。烯丙基和苄基2-乙酰氨基-3,6-二-O-苄基-2-脱氧-β-D-吡喃葡萄糖苷分别提供给体的烯丙基和