Mechanistic Insights of a Concerted Metalation鈥揇eprotonation Reaction with [Cp*RhCl2]2

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• 作者：Aaron P. Walsh ; William D. Jones
• 刊名：Organometallics
• 出版年：2015
• 出版时间：July 13, 2015
• 年：2015
• 卷：34
• 期：13
• 页码：3400-3407
• 全文大小：536K
• ISSN：1520-6041

文摘

The effect of the carboxylate used in a concerted metalation鈥揹eprotonation reaction is probed and shows a direct correlation of pK_a to observed rate up to a pK_a of 4.3, where the rate drops off at higher pK_a. The rate of the C鈥揌 activation of 2-(4-methoxyphenyl)pyridine with [Cp*RhCl₂]₂ and carboxylate follows first-order kinetics in the active metal species, Cp*RhCl(魏²-OAc), and zero-order kinetics in substrate when in a 1:1 ratio. There is a first-order dependence on substrate observed when excess substrate is present. The evaluation of the mechanism using kinetic studies allowed for a mechanistic proposal in which a second Ph鈥睵y coordinates prior to the rate-determining C鈥揌 activation.