Direct chemical synthesis of the β-mannans:: Linear and block syntheses of the alternating β-(l→3)-β-(l→4)-mannan common to Rhodotorula glutinis, Rhodotorula mucilaginosa, and Leptospira biflexa
Direct chemical synthesis of the β-mannans:: Linear and block syntheses of the alternating β-(l→3)-β-(l→4)-mannan common to Rhodotorula glutinis, Rhodotorula mucilaginosa, and Leptospira biflexa
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DOI：
10.1021/ja0471931
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发表时间：
2004-11-24
影响因子：
15
通讯作者：
Li, HM
中科院分区：
文献类型：
--
作者：
Crich, D;Li, WJ;Li, HM
描述了两种立体控制合成交替甘露六糖的甲基糖苷的方法，所述交替甘露六糖代表来自红酵母、粘红酵母和双曲钩端螺旋体的甘露聚糖。两种合成均采用4，6-O-亚苄基-和4，6-O-对甲氧基亚苄基缩醛保护的供体的组合以实现β-甘露糖苷键的立体控制形成。第一种合成是线性的，并且在整个过程中以高度的立体控制进行，总产率为1.9%。第二个合成，嵌段合成，利用两个三联体的偶联，导致更短的序列和4.4%的总产率，尽管在关键步骤中的选择性差。
Two stereocontrolled syntheses of a methyl glycoside of an alternating mannohexaose, representative of the mannan from Rhodotorula glutinis, Rhodotorula mucilaginosa, and Leptospira biflexa, are described. Both syntheses employ a combination of 4,6-O-benzylidene- and 4,6-O-p-methoxybenzylidene acetal-protected donors to achieve stereocontrolled formation of the beta-mannoside linkage. The first synthesis is a linear one and proceeds with a high degree of stereocontrol throughout and an overall yield of 1.9%. The second synthesis, a block synthesis, makes use of the coupling of two trisaccharides, resulting in a shorter sequence and an overall yield of 4.4%, despite the poor selectivity in the key step.