title: Simplification through complexity: the role of Ni-complexes in catalysed diyne-cyclobutanone [4+2+2] cycloadditions, a comparative DFT study.
abstract: A series of density functional theory (DFT) experiments carried out on selected nickel((0))-catalysed diyne-cyclobutanone [4+2+2] cycloadditions provided quantitative confirmation of proposed multistep mechanisms, while clarifying the catalytic role of Ni in the reactions. Geometric and energetic results of the Ni-catalysed process were compared to the one-step non-catalysed complement. Results show the first oxidation to be the rate-determining step, with the intramolecular reaction being the preferred one of the two competing pathways. Ligand-identity is also shown to greatly influence reaction barriers, leading to large deviation in product yields, in direct agreement with experimental observations.
authors.affiliation: College of Chemistry, Beijing Normal University, Beijing, 100875, China. dcfang@bnu.edu.cn.
authors.forename: Jia-Yuan
authors.initials: JY
authors.lastname: Tao
authors.forename: De-Cai
authors.initials: DC
authors.lastname: Fang
authors.forename: Gregory A
authors.initials: GA
authors.lastname: Chass