Stereoselective synthesis of pseudoglycosides catalyzed by TeCl4 under mild conditions
摘要:
Catalytic amounts of tellurium(IV) tetrachloride were used to promote the O-glycosylation of 3,4,6-tri-O-acetyl-D-glucal to give the corresponding 2,3-unsaturated-O-glycosides. With simple alcohols, the desired compounds were obtained in good yields and excellent anomeric selectivity in a short reaction time using only 2 mol % of the catalyst. The application of the method in the synthesis of a small set of glycopyranosides with rigid or flexible linkers gave the corresponding a anomers as products in good yields. Further applications of some of the synthesized compounds in allylation reaction of aldehydes gave the corresponding homoallylic alcohols in good yields. (C) 2012 Elsevier Ltd. All rights reserved.
Environmentally Benign Synthesis of 2,3-Unsaturated Glycopyranosides in Task-Specific Ionic Liquid
作者:Goutam Guchhait、Anup Kumar Misra
DOI:10.1007/s10562-011-0646-7
日期:2011.7
A green reaction condition has been developed for the synthesis of 2,3-unsaturatedglycopyranosides by the Ferrier rearrangement of glycals using alcohols and thiols in 1-butyl-3-methylimidazolium trifluoromethanesulfonate ([BMIM]·OTf) in excellent yield. [BMIM]·OTf has been applied as a task specific ionic liquid organo-catalyst. Operational simplicity, environmentally benign reaction condition, use
Robust perfluorophenylboronic acid-catalyzed stereoselective synthesis of 2,3-unsaturated <i>O</i>-, <i>C</i>-, <i>N</i>- and <i>S</i>-linked glycosides
作者:Madhu Babu Tatina、Xia Mengxin、Rao Peilin、Zaher M A Judeh
DOI:10.3762/bjoc.15.125
日期:——
A convenient protocol was developed for the synthesis of 2,3-unsaturated C-, O-, N- and S-linked glycosides (enosides) using 20 mol % perflurophenylboronic acid catalyst via Ferrier rearrangement. Using this protocol, D-glucals and L-rhamnals reacted with various C-, O-, N- and S-nucleophiles to give a wide range of glycosides in up to 98% yields with mainly α-anomeric selectivity. The perflurophenylboronic
A novel and highly efficient magnetic Fe3O4@C@Fe(III) core–shell catalyst, in which the carbon shell was prepared from lotus leaf, was fabricated. This nanocatalyst was successfully applied in the synthesis of a series of 2,3-unsaturated O-glycosides in excellent yields and with high selectivity, especially in the case of 2-halo O-glycosides, which differ in reactivity from nonsubstituted O-glycosides
Ceric(iv) ammonium nitrate-catalyzed glycosidation of glycals: a facile synthesis of 2,3-unsaturated glycosides
作者:Jhillu S. Yadav、Basi V. Subba Reddy、Sushil Kumar Pandey
DOI:10.1039/b009973m
日期:——
Glycosidation of glycals with alcohols in the presence of a catalytic amount of ceric(IV) ammonium nitrate under neutral conditions proceeds smoothly in refluxing acetonitrile to afford the corresponding 2,3-unsaturated glycosides in excellent yields.
A simple procedure for the synthesis of 2,3-unsaturated glycosides in acetonitrile and tetrahydropyranylation of alcohols and phenols in dichloromethane in the presence of 3,5-dinitrobenzoicacid is described. A variety of alcohols and thiols are reacted with glycals to give the desired products in high yields with high α-selectivity.