Institute of Transformative Bio-Molecules (WPI-ITbM) and Graduate School of Science and §JST, ERATO, Itami Molecular Nanocarbon Project, Nagoya University , Nagoya 464-8602, Japan.
J Am Chem Soc. 2013 Nov 6;135(44):16384-7. doi: 10.1021/ja409803x. Epub 2013 Oct 29.
We describe mechanistic studies of a C-H/C-O biaryl coupling of 1,3-azoles and aryl pivalates catalyzed by Ni(cod)2/dcype. This study not only supports a catalytic cycle consisting of C-O oxidative addition, C-H nickelation, and reductive elimination but also provides insight into the dramatic ligand effect in C-H/C-O coupling. We have achieved the first synthesis, isolation and structure elucidation of an arylnickel(II) pivalate, which is an intermediate in the catalytic cycle after oxidative addition of a C-O bond. Furthermore, kinetic studies and kinetic isotope effect investigations reveal that the C-H nickelation is the turnover-limiting step in the catalytic cycle.
我们描述了 Ni(cod)2/dcype 催化的 1,3-氮唑和芳基频哪醇酯的 C-H/C-O 联芳基偶联的机理研究。这项研究不仅支持了一个包括 C-O 氧化加成、C-H 镍化和还原消除的催化循环，而且还深入了解了 C-H/C-O 偶联中配体的显著影响。我们已经实现了芳基镍(II)频哪酸盐的首次合成、分离和结构阐明，它是 C-O 键氧化加成后催化循环中的中间体。此外，动力学研究和动力学同位素效应研究表明，C-H 镍化是催化循环中的决速步骤。
