Palladium(II)-Catalyzed Oxidative Cascade Cyclization Reactions of Anilides and Anilines: Scope and Mechanistic Investigations
作者:Kai-Tai Yip、Dan Yang
DOI:10.1002/asia.201100242
日期:2011.8.1
catalyst system and molecular oxygen as a green oxidant, acrylanilides and N‐allylanilines undergo oxidative cascade cyclization to form heterocyclic rings in high yields. This methodology is applicable to acrylanilides of different substitution patterns on olefinic units. Mechanistic studies revealed that cyclization of acrylanilides proceeded through an intramolecular syn‐amidopalladation pathway. The
以Pd(OAc)2 /吡啶为催化剂体系,以分子氧为绿色氧化剂,丙烯酰苯胺和N-烯丙基苯胺经过氧化级联环化反应以高产率形成杂环。该方法学适用于烯烃单元上不同取代方式的丙烯酰苯胺。机理研究表明,丙烯酰胺的环化过程是通过分子内合成来进行的。-泛乳化途径。酰胺基palladation的可逆性质是一个“清除过程”,以防止在催化循环中途发生β-氢化物消除,从而有利于级联环化产物的形成。另外,σ-烷基钯物质与链状烯烃CC双键之间的内部配位似乎也不利于β-氢化物的消除。