Overcoming challenges in the palladium-catalyzed synthesis of electron deficient ortho-substituted aryl acetonitriles
作者:Molly C. Brannock、William J. Behof、Gregory Morrison、Christopher B. Gorman
DOI:10.1039/c0ob00903b
日期:——
were effectively synthesized using either a nucleophilic aromatic substitution (NAS) or a palladium-mediated coupling pathway. Synthesis of di-aryl acetonitriles most conveniently proceeded via NAS – palladium-mediated coupling was not required. This reaction, however, results in a product that is more acidic than the reactants. Facile deprotonation of the product prevents efficient formation of the
高度电子不足的单芳基,二芳基和双二芳基乙腈可通过亲核芳族取代(NAS)或钯介导的偶联途径有效合成。二-芳基的合成乙腈最方便地进行经由NAS –不需要钯介导的偶联。然而,该反应产生的产物比反应物更酸性。产物的容易去质子化阻止了双-二芳基乙腈通过NAS途径的有效形成。因此,需要钯介导的偶联来有效地制备双-二芳基乙腈。在钯催化的偶联中,碱和溶剂(以及苄基阴离子亲核试剂的抗衡阳离子)的选择很重要。同样,支持配体的选择也很重要,表明反应对空间和配体电子效应的敏感性。