On the Influence of the C2−O2 and C3−O3 Bonds in 4,6-<i>O</i>-Benzylidene-Directed β-Mannopyranosylation and α-Glucopyranosylation
作者:David Crich、Olga Vinogradova
DOI:10.1021/jo061417b
日期:2006.10.1
3-deoxyarabino-, and 3-deoxyribothioglycosides is described and their glycosylation reactions, with activation by either 1-benzenesulfinyl piperidine/trifluoromethansulfonic anhydride or diphenyl sulfoxide/trifluoromethanesulfonic anhydride, studied. In contrast to the corresponding 4,6-O-benzylidene-protected glucosyl and mannosyl donors, which are α- and β-selective, respectively, poor diastereoselectivity
描述了4,6 - O-亚苄基保护的2-deoxyarabino-,3-deoxyarabino-和3-deoxyribothioglycosides的合成及其糖基化反应,并通过1-苯亚磺酰基哌啶/三氟甲磺酸酐或二苯亚砜/三氟甲烷磺酸酐进行活化,研究过。与分别为α-和β-选择性的相应的4,6 - O-亚苄基保护的葡萄糖基和甘露糖基供体相反,在所有情况下均观察到较差的非对映选择性。根据葡糖基和甘露糖基供体中C2-O2和C3-O3键之间的相互作用以及这种相互作用对中间糖基氧杂碳鎓离子形成的难易程度的影响,讨论了这种选择性差的原因。