Mechanism of Intramolecular Rhodium- and Palladium-Catalyzed Alkene Alkoxyfunctionalizations

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• 作者：Sai Vikrama Chaitanya Vummaleti ; Miasser Al-Ghamdi ; Albert Poater ; Laura Falivene ; Jessica Scaranto ; Dirk J. Beetstra ; Jason G. Morton ; Luigi Cavallo
• 刊名：Organometallics
• 出版年：2015
• 出版时间：December 14, 2015
• 年：2015
• 卷：34
• 期：23
• 页码：5549-5554
• 全文大小：441K
• ISSN：1520-6041

文摘

Density functional theory calculations have been used to investigate the reaction mechanism for the [Rh]-catalyzed intramolecular alkoxyacylation ([Rh] = [Rh^I(dppp)⁺] (dppp, 1,3-bis(diphenylphosphino)propane) and [Pd]/BPh₃ dual catalytic system assisted intramolecular alkoxycyanation ([Pd] = Pd-Xantphos) using acylated and cyanated 2-allylphenol derivatives as substrates, respectively. Our results substantially confirm the proposed mechanism for both [Rh]- and [Pd]/ BPh₃-mediated alkoxyfunctionalizations, offering a detailed geometrical and energetical understanding of all the elementary steps. Furthermore, for the [Rh]-mediated alkoxyacylation, our observations support the hypothesis that the quinoline group of the substrate is crucial to stabilize the acyl metal complex and prevent further decarbonylation. For [Pd]/BPh₃-catalyzed alkoxycyanation, our findings clarify how the Lewis acid BPh₃ cocatalyst accelerates the only slow step of the reaction, corresponding to the oxidative addition of the cyanate O鈥揅N bond to the Pd center.