Mechanism and reactivity of rhodium-catalyzed intermolecular [5+1] cycloaddition of 3-acyloxy-1,4-en

• 作 者: Xiao-Na Ke Casi M.Schienebeck Chen-Chen Zhou Xiu-Fang Xu Wei-Ping Tang
• 机 构: Department of Chemistry,State Key Laboratory of Elemento-Organic Chemistry,Nankai University,School
• 出 处: Chinese Chemical Letters
• 发表日期: 2015年06期
• 关键词: reactivity migration catalyzed intermolecular preferred sequential afford ACE el

The first theoretical study on the mechanism of [Rh Cl(CO)2]2-catalyzed [5 + 1] cycloadditions of 3-acyloxy-1,4-enyne(ACE) and CO has been performed using density functional theory(DFT) calculations.The effect of ester on reactivity of this reaction has been investigated. The computational results have revealed that the preferred catalytic cycle involves the sequential steps of 1,2-acyloxy migration, CO insertion, reductive elimination to form ketene intermediate, 6p-electroncyclization, and aromatization to afford the resorcinol product. The 1,2-acyloxy migration is found to be the rate-determining step of the catalytic cycle. The electron-rich p-dimethylaminobenzoate substrate promotes 1,2-acyloxy migration and significantly increases the reactivity by stabilizing the positive charge building up in the oxocyclic transition state.

The first theoretical study on the mechanism of [Rh Cl (CO) 2] 2-catalyzed [5 + 1] cycloadditions of 3-acyloxy-1,4-enyne (ACE) and CO has been performed using density functional theory (DFT) The computational results have been revealed that the preferred catalytic cycle involves the sequential steps of 1,2-acyloxy migration, CO insertion, reductive elimination to form ketene intermediate, 6p-electroncyclization , and aromatization to afford the resorcinol product. The 1,2-acyloxy migration is found to be the rate-determining step of the catalytic cycle. The electron-rich p-dimethylaminobenzoate substrate promotes 1,2-acyloxy migration and significantly increases the reactivity by stabilizing the positive charge building up in the oxocyclic transition state.