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
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.
Reactivity switching and selective activation of C-1 or C-3 in 2,3-unsaturated thioglycosides
作者:Arunima Mukherjee、Narayanaswamy Jayaraman
DOI:10.1016/j.carres.2011.04.039
日期:2011.9
activation of C-1 or C-3 in 2,3-unsaturated thioglycosides, namely, 2,3-dideoxy-1-thio-D-hex-2-enopyranosides are reported. The reactivity switching allowed activation of either C-1 or C-3, with the use of either N-iodosuccinimide (NIS)/triflic acid (TfOH) or TfOH alone. C-1 glycosylation with alcohol acceptors occurred in the presence of NIS/TfOH, without the acceptors reacting at C-3. On the other
Alkyl 2,3-unsaturatedglycopyranosides have been prepared by the Ferrier rearrangement of acetyl protected glycals catalyzed by HClO 4 -SiO 2 . Operational simplicity, use of economically convenient catalyst, mild reaction conditions, high yields, short reaction times are the key features of this protocol.
The use of ultrastable Y zeolites in the Ferrier rearrangement of acetylated and benzylated glycals
作者:Pieter Levecque、David W. Gammon、Pierre Jacobs、Dirk De Vos、Bert Sels
DOI:10.1039/b921051b
日期:——
The Ferrier rearrangement of a selection of protected glycals was successfully performed using a commercially available H-USY zeolite CBV-720 as catalyst, selected after screening a range of similar catalysts. By incorporating either alcohols, thiophenol, trimethylsilyl azide or allyltrimethylsilane in the reaction it was shown that a range of O-, S-, N- and C-glycosides could be formed. With benzylated glucal and galactal in particular, use of the CBV-720 catalyst led to significantly higher yields of the 2,3-dehydroglycosides than previously reported.