据报道,从胎盘草中分离出的甾族糖苷Sokodoside B的三糖的化学合成。为了获得更好的结果,使用了通过使用固定在二氧化硅上的H 2 SO 4与N-碘代琥珀酰亚胺联用的硫糖苷活化来进行立体选择性,高产的糖基化策略。进行后期TEMPO介导的氧化,以形成所需的糖醛酸部分。还通过使用双糖基化方法制备了靶三糖的类似物。
Organoboron-Promoted Regioselective Glycosylations in the Synthesis of a Saponin-Derived Pentasaccharide from Spergularia ramosa
摘要:
Organoboron-mediated regioselective glycosylations were employed as key steps in the total synthesis of a branched pentasaccharide from a saponin natural product. The ability to use organoboron activation to differentiate OH groups in an unprotected glycosyl acceptor, followed by substrate-controlled reactions of the obtained disaccharide, enabled a streamlining of the synthesis relative to a protective group-based approach. This study revealed a matching/mismatching effect of the relative configuration of donor and acceptor on the efficiency of a regioselective glycosylation reaction, a problem that was solved through the development of a novel boronic acid-amine copromoter system for glycosyl acceptor activation.
Carbamate-bearing carbohydrates contribute to the pharmacological properties of various natural glycosides. The catalytic site-selective carbamoylation of minimally protected pyranosides was achieved for the first time to bypass protection/deprotection sequences. 1-Carbamoylimidazoles were used as the carbamoylation reagents to circumvent the harmful and unstable phosgene and isocyanates. This borinic
Concise synthesis of two trisaccharides related to the saponin isolated from Centratherum anthelminticum
作者:Santanu Mandal、Balaram Mukhopadhyay
DOI:10.1016/j.tet.2007.08.077
日期:2007.11
Chemical synthesis of two trisaccharidesrelated to the saponinisolatedfrom Centratherum anthelminticum is reported. Stereoselective, high-yielding glycosylation strategies were developed using H2SO4 immobilized on silica for activation of trichloroacetimidate donors, or in conjunction with N-iodosuccinimide for activation of a thioglycoside. A late stage TEMPO-mediated oxidation was performed for
报道了从炭疽病菌中分离出的与皂苷有关的两种三糖的化学合成。使用固定在二氧化硅上的H 2 SO 4活化三氯乙酰亚氨酸酯供体,或与N-碘琥珀酰亚胺联用来活化硫糖苷,开发了立体选择性,高产糖基化策略。进行后期TEMPO介导的氧化,以形成所需的糖醛酸部分。
Organoiridium complexes: efficient catalysts for the formation of sugar acetals and ketals
[Cp*IrCl2](2) is used as an efficient promoter for the synthesis of sugar acetals and ketals with good to excellent yields. The catalyst is found to be general for a wide range of sugars. (C) 2011 Elsevier Ltd. All rights reserved.
Organoboron-Promoted Regioselective Glycosylations in the Synthesis of a Saponin-Derived Pentasaccharide from <i>Spergularia ramosa</i>
作者:Ross S. Mancini、Corey A. McClary、Stefi Anthonipillai、Mark S. Taylor
DOI:10.1021/acs.joc.5b00950
日期:2015.9.4
Organoboron-mediated regioselective glycosylations were employed as key steps in the total synthesis of a branched pentasaccharide from a saponin natural product. The ability to use organoboron activation to differentiate OH groups in an unprotected glycosyl acceptor, followed by substrate-controlled reactions of the obtained disaccharide, enabled a streamlining of the synthesis relative to a protective group-based approach. This study revealed a matching/mismatching effect of the relative configuration of donor and acceptor on the efficiency of a regioselective glycosylation reaction, a problem that was solved through the development of a novel boronic acid-amine copromoter system for glycosyl acceptor activation.
Oligosaccharides through reactivity tuning: convergent synthesis of the trisaccharides of the steroid glycoside Sokodoside B isolated from marine sponge Erylus placenta
synthesis of the trisaccharide of the steroid glycoside Sokodoside B isolated from Erylus placenta is reported. Stereoselective, high-yielding glycosylation strategies through thioglycoside activation using H2SO4 immobilized on silica in conjunction with N-iodosuccinimide are used for better results. A late stage TEMPO-mediated oxidation was performed for the formation of required uronic acid moiety. An analog
据报道,从胎盘草中分离出的甾族糖苷Sokodoside B的三糖的化学合成。为了获得更好的结果,使用了通过使用固定在二氧化硅上的H 2 SO 4与N-碘代琥珀酰亚胺联用的硫糖苷活化来进行立体选择性,高产的糖基化策略。进行后期TEMPO介导的氧化,以形成所需的糖醛酸部分。还通过使用双糖基化方法制备了靶三糖的类似物。