PdII-Catalysed CH Functionalisation of Indoles and Pyrroles Assisted by the Removable N-(2-Pyridyl)sulfonyl Group: C2-Alkenylation and Dehydrogenative Homocoupling
作者:Alfonso García-Rubia、Beatriz Urones、Ramón Gómez Arrayás、Juan Carlos Carretero
DOI:10.1002/chem.201001126
日期:2010.8.16
The easily installed and removed N‐(2‐pyridyl)sulfonyl group exerts complete C2 regiocontrol over the PdII‐catalysed CH alkenylation of indoles and pyrroles, affording the corresponding products in good isolated yields (typically ≥70 %). A remarkable feature of this catalyst system is that it tolerates a wide variety of substituted alkenes, including conjugated electron‐deficient alkenes, styrenes
的容易安装和移除ñ - (2-吡啶基)磺酰基施加完整C2区域控制在钯II -催化的Ç ħ吲哚和吡咯,得到良好的分离产率(典型地≥70%)的相应的产品的烯基。该催化剂体系的显着特点是它可以耐受多种取代的烯烃,包括共轭电子不足的烯烃,苯乙烯和1,3-二烯以及共轭1,1和1,2-二取代的烯烃。最终的还原性脱磺酰化反应可得到高收率的C2取代的游离NH吲哚和吡咯。这个N(2-吡啶基)磺酰基导向策略也已扩展到吲哚分子间,脱氢均偶联的规程的开发,提供了2,2'-双吲哚。基于与同位素标记的起始原料反应的反应机理研究以及对各种电子底物的竞争动力学研究表明,存在螯合辅助的亲电子芳族取代palladation机制。