作者:Howard I. Duynstee、Martijn C. de Koning、Gijs A. van der Marel、Jacques H. van Boom
DOI:10.1016/s0040-4020(99)00527-x
日期:1999.8
Chemoselective NIS/ cat. TfOH-mediated glycosylation of ethyl2,3,4-tri-O-benzoyl-1-thio-β-d-glucopyranoside (13) with ethyl2,3-di-O-acetyl-5-O-benzyl-1-thio-αβ-d-erythro-apiofuranoside (4a) gave dimer14 in an excellent yield. BF3•Et2O-catalysed condensation of the α-trichloroacetimidate31, accessible in two steps from14, with 3,4,5-trimethoxyphenol gave β-linked derivative32 followed by deprotection
化学选择性NIS /猫。TfOH介导的乙基2,3,4-三-O-苯甲酰基-1-硫代-β-d-吡喃葡萄糖苷(13)与乙基2,3-二-O-乙酰基-5-O-苄基-1-硫代-的糖基化作用αβ-d-赤型-呋喃呋喃糖苷(4a)以优异的产率得到二聚体14。BF 3 •Et 2 O催化的α-三氯乙酰亚胺酸酯31的缩合反应(从14步可分两个步骤进行)与3,4,5-三甲氧基苯酚生成β-连接的衍生物32,然后脱保护得到KelampayosideA。保护基的操作为32和所得的后续caffeoylation 36接着进行脱保护,得到Kelampayoside B.图选项