Davies David L, Donald Steven M A, Macgregor Stuart A
Department of Chemistry, University of Leicester, Leicester LE1 7RH, UK.
J Am Chem Soc. 2005 Oct 12;127(40):13754-5. doi: 10.1021/ja052047w.
Various mechanisms for the cyclometalation of dimethylbenzylamine by palladium acetate have been studied by DFT calculations. Contrary to previous suggestions, the rate-limiting step is the electrophilic attack of the palladium on an ortho arene C-H bond to form an agostic complex rather than a Wheland intermediate. The cyclometalated product is then formed by intramolecular deprotonation by acetate via a six-membered transition state; this step has almost no activation barrier.
通过密度泛函理论计算研究了醋酸钯使二甲基苄胺发生环金属化的各种机理。与之前的推测相反，限速步骤是钯对邻位芳基C-H键的亲电进攻以形成一个agostic配合物，而不是一个Wheland中间体。然后，环金属化产物通过醋酸根经由六元过渡态进行分子内去质子化而形成；这一步几乎没有活化能垒。
