Palladium-Catalyzed Regioselective 5-<i>exo</i>-<i>O</i>-Cyclization/Oxidative Heck Cascades from<i>o</i>-Alkynylbenzamides and Electron-Deficient Alkenes
作者:Youssef Madich、Rosana Álvarez、José M. Aurrecoechea
DOI:10.1002/ejoc.201402709
日期:2014.10
Pd-catalyzed 5-exo-selective oxycyclization/oxidative Heck coupling cascade is described, starting from readily available ortho-alkynylbenzamides and functionalized olefins. The key to a high regioselectivity in the cyclization step is the choice of catalyst and/or additives. Thus, Pd(OAc)2 provides the desired 5-exo products predominantly, whereas with PdCl2 or Pd(TFA)2, the corresponding 6-endo products
描述了 Pd 催化的 5-外选择性氧环化/氧化 Heck 偶联级联,从容易获得的邻炔基苯甲酰胺和功能化烯烃开始。环化步骤中高区域选择性的关键是催化剂和/或添加剂的选择。因此,Pd(OAc)2 主要提供所需的 5-exo 产物,而对于 PdCl2 或 Pd(TFA)2,相应的 6-endo 产物占优势。随后的氧化 Heck 型偶联发生立体选择性,E 异构体的形成占主导地位,从而有效制备结构多样的羰基取代的烯丙基异苯并呋喃亚胺。