Efficient Access to All‐Carbon Quaternary and Tertiary α‐Functionalized Homoallyl‐type Aldehydes from Ketones
作者:Vittorio Pace、Laura Castoldi、Eugenia Mazzeo、Marta Rui、Thierry Langer、Wolfgang Holzer
DOI:10.1002/anie.201706236
日期:2017.10.2
β,γ‐Unsaturated aldehydes with all‐carbon quaternary or tertiary α‐centers were rapidly assembled from ketones through a unique synthetic operation consisting of 1) C1 homologation, 2) Lewis acid mediated epoxide–aldehyde isomerization, and 3) electrophilic trapping. The synthetic equivalence of a vinyl oxirane and a β,γ‐unsaturated aldehyde is the key concept of this previously undisclosed tactic
具有全碳四元或三元α-中心的β,γ-不饱和醛通过一种独特的合成操作由酮快速组装而成,该合成操作包括1)C 1同源,2)Lewis酸介导的环氧-醛异构化和3)亲电捕集。乙烯基环氧乙烷和β,γ-不饱和醛的合成当量是这种以前未公开的策略的关键概念。机理研究和标记实验表明,烯醇醛是重要的中间体。同源类胡萝卜素的形成在确定化学选择性中起关键作用。