Regioselective Glycosylation of Unprotected Phenyl 1-Thioglycopyranosides with Phenylboronic Acid as a Transient Masking Group
作者:Thomas Hauch Fenger、Robert Madsen
DOI:10.1002/ejoc.201300723
日期:2013.9
A useful protocol is described for the regioselective glycosylation of the secondary alcohols in unprotected glycosyl acceptors. Phenyl 1-thioglycopyranosides derived from D-glucose, D-galactose, D-glucosamine, L-rhamnose, and L-fucose were treated with phenylboronic acid to install a temporary boronic ester, and then submitted to a Koenigs–Knorr glycosylation with perbenzoylated glucopyranosyl or galactopyranosyl
描述了一个有用的协议,用于在未保护的糖基受体中对仲醇进行区域选择性糖基化。衍生自 D-葡萄糖、D-半乳糖、D-葡萄糖胺、L-鼠李糖和 L-岩藻糖的苯基 1-硫代吡喃糖苷用苯基硼酸处理以安装临时硼酸酯,然后用过苯甲酰化吡喃葡萄糖基进行 Koenigs-Knorr 糖基化或吡喃半乳糖基溴化物。与葡萄糖苷和半乳糖苷的 3-位偶联获得了良好的产率,但其他受体的产率较低。使用苯基 1-硫代-β-D-吡喃葡萄糖苷,也可以通过超臂硫代半乳糖苷供体实现偶联。来自葡萄糖-葡萄糖偶联的产物可以在 6 位进行第二次区域选择性糖基化。在半乳糖系列中,