Rhodium-Catalyzed [6 + 2] Cycloaddition of Internal Alkynes with Cycloheptatriene: Catalytic Study and DFT Calculations of the Reaction Mechanism

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• 作者：Xinrui Zhang ; Jingjing Wang ; Hui Zhao ; Haitao Zhao ; Jianhui Wang
• 刊名：Organometallics
• 出版年：2013
• 出版时间：June 24, 2013
• 年：2013
• 卷：32
• 期：12
• 页码：3529-3536
• 全文大小：367K
• 年卷期：v.32,no.12(June 24, 2013)
• ISSN：1520-6041

文摘

A rhodium-catalyzed [6 + 2] cycloaddition of internal alkynes with cycloheptatriene is described. A series of substituted alkynes were cycloadded to cycloheptatriene through a [6 + 2] addition to give a variety of substituted bicyclic compounds in excellent yields. The optimal catalytic system for these transformations was a [Rh(COD)Cl]₂ (5.0 mol %) catalyst in combination with CuI (10 mol %) and PPh₃ (10 mol %). The proposed mechanism for this system includes an initial oxidative coupling reaction between the coordinated cycloheptatriene and the internal alkyne, followed by a [1,3]-shift of the Rh metal center and a reductive elimination from the Rh(III)鈥揳llyl complex to give the final product. Calculations using a model Rh(I) catalyst were also carried out to further understand this mechanism.