的产生和2命运I-VII,3 I-VII,6 II-VII -icosa- ø -甲基- β-cyclomaltoheptaos-6我- ö还原条件下基自由基进行说明。涉及两个自由基级联反应:主要的一个是在5 VII C由氢的1,8-HAT引发。该自由基可以通过六步顺序在三个糖单元之前于1 V C到达异头氢。在5组14个氢化物允许一个选择性地停止所述级联的不同供氢能力VII C,2 VI C,和4 VI ℃以得到β-CD与β-升-Ido p 单元,无环七糖和六糖结构。
Regioselectivity in the ring opening of 2-phenyl-1,3-dioxan-2-yl radicals derived from cyclic benzylidene acetals and comparison with deoxygenation of a carbohydrate diol via its cyclic thionocarbonate
作者:Brian P Roberts、Teika M Smits
DOI:10.1016/s0040-4039(01)00540-8
日期:2001.5
Ring-opening β-scission of monocyclic 2-phenyl-1,3-dioxan-2-yl radicals gives preferentially the more stabilised alkyl radical. However, analogous bicyclic radicalsderived from two 4,6-O-benzylidene glucopyranosides afford primary radicals in preference to secondary radicals, a result that can be rationalised with the aid of DFT calculations. The report by Barton and Subramanian, that the opposite
The synthesis of optically active tetrahydropyrans by the addition of a stabilised Witting reagent to pyranose sugars
作者:Nigel J. Barnes、Alan H. Davidson、Leslie R. Hughes、Garry Procter
DOI:10.1039/c39850001292
日期:——
The addition of the phosphonate–sulphone (8) to the carbohydrates (9) and (10) gave the tetrehydropyrans (11) and (12) as mixtures of α- and β-isomers; treatment of the mixture with sodium hydride gave the purer β-isomers.
Reductive Radical Cascades Triggered by Alkoxyl Radicals in the β-Cyclodextrin Framework
作者:Elisa I. León、Angeles Martín、Inés Pérez-Martín、Ernesto Suárez
DOI:10.1021/acs.orglett.8b01308
日期:2018.6.1
The generation and fate of 2I–VII,3I–VII,6II–VII-icosa-O-methyl-β-cyclomaltoheptaos-6I-O-yl radical under reductive conditions is described. Two radical cascade reactions are involved: the main one is triggered by a 1,8-HAT of the hydrogen at 5VIIC. The radical can reach the anomeric hydrogen at 1VC three sugar units ahead using a six-step sequence. The different hydrogen donor ability of the group
的产生和2命运I-VII,3 I-VII,6 II-VII -icosa- ø -甲基- β-cyclomaltoheptaos-6我- ö还原条件下基自由基进行说明。涉及两个自由基级联反应:主要的一个是在5 VII C由氢的1,8-HAT引发。该自由基可以通过六步顺序在三个糖单元之前于1 V C到达异头氢。在5组14个氢化物允许一个选择性地停止所述级联的不同供氢能力VII C,2 VI C,和4 VI ℃以得到β-CD与β-升-Ido p 单元,无环七糖和六糖结构。