Synthetic Strategies Directed Towards 5a-Carbahexopyranoses and Derivatives Based on 6-endo-trig Radical Cyclizations
作者:Ana M. Gómez、Clara Uriel、Maria D. Company、J. Cristóbal López
DOI:10.1002/ejoc.201100956
日期:2011.12
Several synthetic strategies directed towards 5a-carbahexopyranoses and based on 6-endo-trig radical cyclization of unsaturated carbohydrate derivatives have been devised. Three elements for regiocontrol to optimize the 6-endo/5-exo ratio have been incorporated, and their efficiencies in directing 6-endo cyclizations have been evaluated. These elements – namely: i) the incorporation of a substituent
已经设计了几种针对 5α-碳己基吡喃糖并基于不饱和碳水化合物衍生物的 6-endo-trig 自由基环化的合成策略。纳入了三个用于区域控制以优化 6-endo / 5-exo 比率的元素,并评估了它们在指导 6-endo 环化方面的效率。这些元素 - 即:i)在 C-5(自由基编号)处引入取代基,ii)使用乙烯基(而不是烷基)基团,以及 iii) 在系统中包含环应变 - 已被证明是有用的组合使用时。它们中的两个同时存在也会导致 6-endo 选择性。在另一个主题上,随后的烯基烷烃臭氧化以提供二醇似乎是基于锡-氧重排,类似于相关乙烯基硅烷的报道,