Autocatalysis for C鈥揌 Bond Activation by Ruthenium(II) Complexes in Catalytic Arylation of Functional Arenes
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- 作者：Emmanuel Ferrer Flegeau ; Christian Bruneau ; Pierre H. Dixneuf ; Anny Jutand
- 刊名：Journal of the American Chemical Society
- 出版年：2011
- 出版时间：July 6, 2011
- 年：2011
- 卷：133
- 期：26
- 页码：10161-10170
- 全文大小：1201K
- 年卷期：v.133,no.26(July 6, 2011)
- ISSN：1520-5126
文摘
Kinetic data for the C鈥揌 bond activation of 2-phenylpyridine by RuII(carboxylate)2(p-cymene) I (acetate) and I鈥?/b> (pivalate) are available for the first time. They reveal an irreversible autocatalytic process catalyzed by the coproduct HOAc or HOPiv (acetonitrile, 27 掳C). The overall reaction is indeed accelerated by the carboxylic acid coproduct and water. It is retarded by a base, in agreement with an autocatalytic process induced by HOAc or HOPiv that favors the dissociation of one carboxylate ligand from I and I鈥?/b> and consequently the ensuing complexation of 2-phenylpyridine (2-PhPy). The C鈥揌 bond activation initially delivers Ru(O2CR)(o-C6H4-Py)(p-cymene) A or A鈥?/b>, containing one carboxylate ligand (OAc or OPiv, respectively). The overall reaction is accelerated by added acetates. Consequently, C鈥揌 bond activation (faster for acetate I than for pivalate I鈥?/b>) proceeds via an intermolecular deprotonation of the C鈥揌 bond of the ligated 2-PhPy by the acetate or pivalate anion released from I or I鈥?/b>, respectively. The 18e complexes A and A鈥?/b> easily dissociate, by displacement of the carboxylate by the solvent (also favored by the carboxylic acid), to give the same cationic complex B+ {[Ru(o-C6H4-Py)(p-cymene)(MeCN)]+}. Complex B+ is reactive toward oxidative addition of phenyl iodide, leading to the diphenylated 2-pyridylbenzene.