Late-Stage C–H Alkylation of Heterocycles and 1,4-Quinones via Oxidative Homolysis of 1,4-Dihydropyridines
作者:Álvaro Gutiérrez-Bonet、Camille Remeur、Jennifer K. Matsui、Gary A. Molander
DOI:10.1021/jacs.7b05899
日期:2017.9.6
heterocyclic bases and 1,4-quinones. DHPs are readily prepared from aldehydes, and considering that aldehydes normally require harsh reaction conditions to take part in such transformations, with mixtures of alkylated and acylated products often being obtained, this net decarbonylative alkylation approach becomes particularly useful. The present method takes place under mild reaction conditions and requires
在氧化条件下,1,4-二氢吡啶 (DHP) 发生均裂,仅形成以 Csp3 为中心的自由基,该自由基可以参与杂环碱基和 1,4-醌的 CH 烷基化。DHP很容易由醛制备,并且考虑到醛通常需要苛刻的反应条件来参与这种转化,并且经常获得烷基化和酰化产物的混合物,这种净脱羰烷基化方法变得特别有用。本方法在温和的反应条件下进行,仅需要过硫酸盐作为化学计量氧化剂,使得该方法适合复杂分子的后期CH烷基化。值得注意的是,结构复杂的药剂可以用该方案功能化或制备,例如抗疟药 Atovaquone 和抗疟药 Parvaquone,从而证明其适用性。机理研究揭示了可能通过形成脱芳构中间体的自由基链过程,从而更深入地了解控制这些自由基前体反应性的因素。