Nickel- and Palladium-Catalyzed Homocoupling of Aryl Triflates. Scope, Limitation, and Mechanistic Aspects
作者:Anny Jutand、Adil Mosleh
DOI:10.1021/jo961464b
日期:1997.1.1
the homocoupling of 1-naphthyl triflate, since the dimer was obtained in almost quantitative yield. However, the homocoupling is sensitive to steric hindrance, excluding for the moment the synthesis of atropisomers. The homocoupling proceeds via an activation of the C-O bond of the aryl triflate by a palladium(0) (or a nickel(0)) complex, providing an intermediate arylpalladium(II) (or nickel(II))
芳基三氟甲磺酸酯的直接还原主要提供酚和一些芳烃,而催化量的钯或镍的存在导致联芳基的形成。均相耦合在电子源(阴极或锌粉)的存在下进行。对金属(镍或钯),配体(单齿或双齿膦)和还原过程(电化学或化学)的明智选择可以合成功能对称的联芳基。由二齿配体如NiCl(2)(dppf)和Pd(OAc)(2)+1 BINAP连接的镍和钯配合物对于1-萘基三氟甲磺酸酯的均偶联非常有效,因为二聚体几乎以定量获得。但是,均一耦合对空间位阻敏感,目前不包括阻转异构体的合成。