Li Z J, Wang L B, Huang Z T
Institute of Chemistry, Academia Sinica, Beijing, People's Republic of China.
Carbohydr Res. 1996 Dec 13;295:77-89. doi: 10.1016/s0008-6215(96)90124-x.
The synthesis and reactions of glycopyranosyl heterocyclic ketene aminals were investigated. Under mild conditions, the benzoyl-substituted heterocyclic ketene aminals 3 or 4 underwent O-glycosylation with tetra-O-acetyl-alpha-D-glucopyranosyl bromide (1) using mercuric cyanide or silver trifluoromethanesulfonate as catalyst in acetonitrile to give O-glycopyranosyl heterocyclic ketene aminals 5-7 and 8-11, respectively. The beta-anomers were the sole products. By the O-glycosylation of heterocyclic ketene aminals with 1, the O-attack of heterocyclic ketene aminals was carried out for the first time. Some of 5-11 in the synthesis of oligosaccharides 14 and 15 can provide a valuable leaving group at the anomeric position of the glycopyranosyl ring. Compounds 6c or 10c may be potentially useful as glycosyl donors in the synthesis of oligosaccharides.
对吡喃糖基杂环烯酮缩胺的合成及反应进行了研究。在温和条件下，苯甲酰基取代的杂环烯酮缩胺3或4在乙腈中，以氰化汞或三氟甲磺酸银作为催化剂，与四 - O - 乙酰基 - α - D - 吡喃葡萄糖基溴（1）发生O - 糖基化反应，分别得到O - 吡喃糖基杂环烯酮缩胺5 - 7和8 - 11。β - 端基异构体是唯一产物。通过杂环烯酮缩胺与1的O - 糖基化反应，首次实现了杂环烯酮缩胺的O - 进攻。在寡糖14和15的合成中，5 - 11中的一些化合物可在吡喃糖基环的异头位置提供一个有价值的离去基团。化合物6c或10c在寡糖合成中可能作为潜在有用的糖基供体。
