Stereoselective synthesis of C-ketosides by sequential intramolecular hydrogen atom transfer–intermolecular allylation reaction
作者:Angeles Martín、Inés Pérez-Martín、Luis M. Quintanal、Ernesto Suárez
DOI:10.1016/j.tetlet.2008.06.070
日期:2008.8
A tandem 1,5 or 1,6 hydrogen atom transfer (HAT)-radical allylation using carbohydrate models is described. The HAT reaction generated a C-glycos-1-yl radical intermediate, which added to allyltri-n-butyltin with high diastereoselectivity, to give C-ketosides with the quaternary carbon carrying two differently functionalized tethers. (C) 2008 Elsevier Ltd. All rights reserved.
Hydrogen atom transfer experiments provide chemical evidence for the conformational differences between C- and O-glycosides
作者:Angeles Martín、Luis M. Quintanal、Ernesto Suárez
DOI:10.1016/j.tetlet.2007.05.166
日期:2007.7
reaction promoted by alkoxyl radicals generated from 3-hydroxypropyl α-d-mannopyranoside derivative (O-glycoside) and 2,6-anhydro-d-glycero-d-manno-decitol derivative (C-glycoside) is studied. The O-glycoside model abstracts preferentially the hydrogen atom at C-5 (1,8-HAT) while the C-glycoside abstracts the hydrogen atom at C-1 (1,6-HAT) but no abstraction at C-5 could be detected. These results are explained