Glycosyl phosphonium halide as a reactive intermediate in highly α-selective glycosylation
Glycosyl phosphonium halide as a reactive intermediate in highly α-selective glycosylation
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DOI：
10.1246/bcsj.78.910
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发表时间：
2005-05-15
影响因子：
4
通讯作者：
Mukaiyama, T
中科院分区：
文献类型：
--
作者：
Kobashi, Y;Mukaiyama, T
几种糖基受体与2，3，4，6-四-O-苄基-D-吡喃葡萄糖溴(4)在CH2Cl2中的高α-选择性糖基化反应或通过糖基溴化膦中间体回流CHCl3的反应在室温下顺利进行，相应的二糖的产率和选择性都很高。此外，以乙酸乙酯为起始原料，以三甲基硅烷和氧膦为起始原料，在CH2Cl2中进行的一锅法糖基化反应在室温下也能有效地进行，得到相应的二糖，尽管这种通过原位异构化一锅法合成α-糖苷的方法被认为是困难的，因为糖基卤化物很容易与三甲基硅基乙酸酯反应生成起始糖基供体乙酸糖酯。
Highly alpha-selective glycosylations of several glycosyl acceptors with 2,3,4,6-tetra-O-benzyl-D-glucopyranosyl bromide (4) proceeded smoothly in the presence of tri(1-pyrrolidino)phosphine oxide in CH2Cl2 at room temperature or in refluxing CHCl3 via glycosyl phosphonium bromide intermediates and the corresponding disaccharides were afforded in good yields with high selectivities. Further, the one-pot glycosylation starting from glycosyl acetate using iodotrimethylsilane and phosphine oxide also proceeded efficiently in CH2Cl2 at room temperature to give the corresponding disaccharides, although this one-pot synthesis of alpha-glycoside via in situ anomerization procedure is considered difficult because glycosyl halide reacts with trimethylsilyl acetate easily to regenerate glycosyl acetate, a starting glycosyl donor.