Stereospecific debenzylative cycloetherification of carbohydrate-derived allylic alcohols, ethers and esters to form vinyl C-furanosides
作者:Riccardo Cribiù、Ian Cumpstey
DOI:10.1039/b718060h
日期:——
Benzyl ether protected polyhydroxylated alkene compounds containing allylic alcohol, ether or ester functionality undergo a stereospecific cyclisation reaction upon treatment with TFA-acetonitrile-toluene with inversion of configuration at the allylic position and loss of a benzyl ether to give tetrahydrofurans.
Formation and selective rupture of 1,4-anhydroseptanoses
作者:Raghu Vannam、Aditya R. Pote、Mark W. Peczuh
DOI:10.1016/j.tet.2016.12.031
日期:2017.1
Formation 1,4-anhydroseptanose sugars via intramolecular attack of a benzyl ether oxygen onto an anomeric electrophile is reported. The regioselectivity of the cyclization was confirmed by NMR spectroscopy and an X-ray structure of a glucose-derived 1,4-anhydroseptanose. The transformation is relatively general and was applied to septanoses derived from glucose, mannose, xylose, and galactose. Regioselective
Synthesis of <i>C</i>-Septanosides from Pyranoses via Vinyl Addition and Electrophilic Cyclization
作者:Raghu Vannam、Mark W. Peczuh
DOI:10.1021/ol401769k
日期:2013.8.16
A two-stepsynthesis of C-septanosides from pyranoses is reported. Vinyl addition to tetra-O-benzyl d-glucose, d-galactose, and d-mannose gave the corresponding allylic alcohols. Electrophilic cyclization followed by treatment with iodine gave iodomethyl C-septanosides suitable for substitution reactions. The cyclizations were diastereoselective, giving cis-1,2 configured C-septanosides. Selectivity
On the synthesis of vinyl and phenyl C-furanosides by stereospecific debenzylative cycloetherification
作者:Riccardo Cribiù、K. Eszter Borbas、Ian Cumpstey
DOI:10.1016/j.tet.2009.01.014
日期:2009.3
diastereoselectivity of addition is dependent on whether a Grignard reagent or a trialkylzincate reagent is used. The open-chain compounds undergo a stereospecific cyclisation reaction on treatment with catalytic strong Brønsted acid with heating to form tetrahydrofurans with inversion of configuration at the allylic or benzylic carbon (C-1) and loss of hydroxyl from this position. A short synthesis