Efficient Syntheses of β-Cyanosugars Using Glycosyl Iodides Derived from Per-O-silylated Mono- and Disaccharides
摘要:
[GRAPHICS]Reported herein is a general method for the efficient syntheses of a variety of beta -cyano glycosides through the activation of per-O-trimethylsllyl glycosides with TMSI to form alpha -glycosyl iodides, which undergo S(N)2-type displacement when treated with tetrabutylammonium cyanide. The cyanoglycosides were reduced under mild conditions using NaBH4 in the presence of catalytic CoCl2(H2O)(6) in THF/H2O to give the corresponding aminomethyl glycosides.
Simple one-pot regioselective 6-O-phosphorylation of carbohydrates and trehalose desymmetrization
作者:A. Abragam Joseph、Chun-Wei Chang、Cheng-Chung Wang
DOI:10.1039/c3cc47180b
日期:——
Biologically essential carbohydrate 6-phosphates, especially trehalose 6-phosphate, can be synthesized easily in excellent overall yields in 2 steps involving minimum protecting group manipulations. We can cleave the diphenylphosphate group for further synthetic objectives.
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。