Intramolecular 1,5- versus 1,6-Hydrogen Abstraction Reaction Promoted by Alkoxy Radicals in Carbohydrate Models
作者:Cosme G. Francisco、Raimundo Freire、Antonio J. Herrera、Inés Peréz-Martín、Ernesto Suárez
DOI:10.1021/ol025981u
日期:2002.5.1
[GRAPHICS]The alkoxy radical generated by reaction of 3,7-anhydro-2-deoxyoctitols with (diacetoxyiodo)benzene (DIB) and iodine abstracts regioselectively either the proton at C7 or that at C4 depending on the electronegativity of the substituent at C4. The correct election of this substituent can switch the reaction to give 2,9-dioxabicyclo[3.3.1]nonane or hexahydro-2H-furo[3,2-b]pyran ring systems.
Intramolecular 1,5- versus 1,6-hydrogen abstraction reaction promoted by alkoxyl radicals in pyranose and furanose models
作者:Cosme G. Francisco、Raimundo Freire、Antonio J. Herrera、Inés Pérez-Martín、Ernesto Suárez
DOI:10.1016/j.tet.2007.06.023
日期:2007.9
The primary alkoxyl radical generated by reaction of 1-(2-hydroxyethyl)-glycosides with (diacetoxyiodo)benzene (DIB) and iodine can undergo regioselective intramolecular hydrogen abstraction (IHA) reactions to furnish four different dioxabicyclic systems derived from carbohydrates. The results strongly suggest that the regiocontrol and feasibility of the cyclisation are dependant not only on geometric