Kochetkov N K, Betaneli V I, Kryazhevskikh I A
N.D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Moscow.
Carbohydr Res. 1993 May 21;244(1):85-97. doi: 10.1016/0008-6215(93)80006-z.
3,4,6-Tri-O-acetyl-1,2-O-(1-cyanobenzylidene)-alpha-D-galactopy ranoses with differently substituted aromatic nuclei have been synthesised and used as glycosyl donors in reactions with the acceptors methyl 2,3,4-tri-O-acetyl-6-O-trityl-beta-D-galactopyranoside (11) and methyl 2,4,6-tri-O-acetyl-3-O-trityl-beta-D-galactopyranoside (12). The glycosylation of 11 gave only beta products. The effeciency and stereoselectivity of the glycosylations of 12 depend on the nature of the substituent in the aromatic ring. The stereoselectivity for the formation of 1,2-trans-glycosidic bonds was the highest with the p-methoxy-benzylidene derivative with triphenylmethylium triflate as the promoter.
已合成了具有不同取代芳核的3,4,6-三-O-乙酰基-1,2-O-(1-氰基亚苄基)-α-D-吡喃半乳糖，并将其用作糖基供体，用于与受体2,3,4-三-O-乙酰基-6-O-三苯甲基-β-D-吡喃半乳糖苷甲酯(11)和2,4,6-三-O-乙酰基-3-O-三苯甲基-β-D-吡喃半乳糖苷甲酯(12)的反应。11的糖基化反应只生成β产物。12的糖基化反应的效率和立体选择性取决于芳环中取代基的性质。以对甲氧基亚苄基衍生物与三氟甲磺酸三苯甲鎓作为促进剂时，形成1,2-反式糖苷键的立体选择性最高。
