Selective C−O Bond Cleavage of Sugars with Hydrosilanes Catalyzed by Piers’ Borane Generated In Situ
作者:Jianbo Zhang、Sehoon Park、Sukbok Chang
DOI:10.1002/anie.201708109
日期:2017.10.23
[(C6F5)2BH], generated in situ, is demonstrated to promote the hydrosilylative reduction of sugars, providing a series of linear or cyclic polyols with high chemo- and regioselectivities undermildconditions. Studies of catalytic reactivity and regioselectivity with regard to the C−O bond cleavage with hydrosilanes suggest an importance of the steric environment around the anomeric carboncenter of the
Piers的硼烷[(C 6 F 5)2 BH]原位生成,可促进糖的氢化硅烷化还原,在温和条件下提供一系列具有高化学选择性和区域选择性的线性或环状多元醇。关于用氢硅烷裂解C-O键的催化反应性和区域选择性的研究表明,糖异头碳中心周围的空间环境很重要。
Regioselective azidotrimethylsilylation of carbohydrates and applications thereof
Azidotrimethylsilylation of carbohydrates (monosaccharides and disaccharides) has been achieved in high yields under Mitsunobu conditions. The azidation of carbohydrates is effected at 0 °C essentially only at the primary alcoholic position in mono, di- and triols in protected/unprotected glycosides, whereas the remaining secondary hydroxyl groups got silylated. Surprisingly, no azidation of the secondary hydroxyls was observed in all the carbohydrate substrates. Applications of the methodology for the synthesis of amino sugars, triazoles and azasugars are reported.
Organosilylderivate von Dicarbonsäuren, Oxycarbonsäuren und Zuckern
作者:F. A. Henglein、G. Abelsnes、H. Heneka、Kl. Lienhard、Pr. Nakhre、K. Scheinost
DOI:10.1002/macp.1957.020240101
日期:——
AbstractDurch Reaktionen von Alkyl‐und Arylchlorsilanen mit Terephthalsäure, Fumarsäure, Sebacinsäure, Milchsäure und Weinsäure sowie mit Glucose, Galaktose, Fructose, Saccharose und Dextrin (in Gegenwart von Pyridin) wurden die entsprechenden monomeren und polymeren Silylester bzw. Silyläther dargestellt. Die Eigenschaften der erhaltenen Verbindungen werden beschrieben.
Highly atom economical uncatalysed and I2-catalysed silylation of phenols, alcohols and carbohydrates, using HMDS under solvent-free reaction conditions (SFRC)
作者:Marjan Jereb
DOI:10.1016/j.tet.2012.03.040
日期:2012.5
An uncatalysed silylation of phenols, regardless on the aggregate state and nature of the substituents with 0.55 equiv of HMDS under solvent-free reaction conditions (SFRC) at room temperature is reported. Sterically hindered phenols, carbohydrates and most of the alcohols additionally required a catalytic amount (up to 2 mol%) of iodine. The reaction protocol is very simple; obtaining a pure product, particularly of uncatalysed reactions, was frequently a completely solvent-free process. (C) 2012 Elsevier Ltd. All rights reserved.
Boron Compounds; LV<sup>1</sup>. A New<i>O</i>-Silylation Method via Diethylboryl Ethers and Esters