Solvent/Base Effects in the Selective Domino Synthesis of Phenanthridinones That Involves High-Valent Palladium Species: Experimental and Theoretical Studies
作者:Ludovic Donati、Pascale Leproux、Elise Prost、Sylvie Michel、François Tillequin、Vincent Gandon、François-Hugues Porée
DOI:10.1002/chem.201101354
日期:2011.11.4
The domino reaction of o‐bromobenzamides 1 a–m in the presence of K2CO3 and the [PdCl2(PPh3)2] catalyst granted a selective access to phenanthridinones 2 or to the new 1‐carboxamide phenanthridinones 3 depending on the solvent, DMF or 1,4‐dioxane, respectively. Investigations of the reaction parameters provided the first example of a direct correlation between the base dissociation and the solvent
邻溴苯甲酰胺1 a – m在K 2 CO 3和[PdCl 2(PPh 3)2 ]催化剂的存在下的多米诺反应允许选择性地利用菲啶酮2或新的1-羧酰胺菲啶酮3,具体取决于分别是DMF或1,4-二恶烷。对反应参数的研究为碱解离和溶剂极性与所观察到的选择性之间的直接相关提供了第一个例子。此外,机理研究(NMR光谱和ESI-MS监测)使我们能够表征Pd II palladacycle4和联芳基物质是这两个多米诺骨牌工艺的常见中间体。在此基础上,可以设想通过在Pd II palladacycle 4中氧化添加1后生成Pd IV络合物来形成C(sp 2)C(sp 2)键,这一原理得到DFT计算的支持。提出了一般的催化循环来解释这些观察结果。