title: Mechanism and Reactivity of Rh-Catalyzed Intermolecular [5+1] Cycloaddition of 3-Acyloxy-1,4-Enyne (ACE) and CO: A Computational Study.
abstract: The first theoretical study on the mechanism of [RhCl(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, 6π-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-richp-dimethylaminobenzoate substrate promotes 1,2-acyloxy migration and significantly increases the reactivity by stabilizing the positive charge building up in the oxocyclic transition state.
authors.affiliation: Department of Chemistry, State Key Laboratory of Elemento-organic Chemistry, Nankai University, Tianjin, 300071, P. R. China.
authors.forename: Xiao-Na
authors.initials: XN
authors.lastname: Ke
authors.affiliation: School of Pharmacy and Department of Chemistry, University of Wisconsin, Madison, WI 53705-2222.
authors.forename: Casi M
authors.initials: CM
authors.lastname: Schienebeck
authors.affiliation: Department of Chemistry, State Key Laboratory of Elemento-organic Chemistry, Nankai University, Tianjin, 300071, P. R. China.
authors.forename: Chen-Chen
authors.initials: CC
authors.lastname: Zhou
authors.affiliation: Department of Chemistry, State Key Laboratory of Elemento-organic Chemistry, Nankai University, Tianjin, 300071, P. R. China.
authors.forename: Xiufang
authors.initials: X
authors.lastname: Xu
authors.affiliation: School of Pharmacy and Department of Chemistry, University of Wisconsin, Madison, WI 53705-2222.
authors.forename: Weiping
authors.initials: W
authors.lastname: Tang
keywords: (5+1) Cycloaddition; DFT; Ester effect; Rhodium catalyst