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Accessing Valuable Ligand Supports for Transition Metals: A Modified, Intermediate Scale Preparation of 1,2,3,4,5-Pentamethylcyclopentadiene
Published on: March 20, 2017
Simplification through complexity: the role of Ni-complexes in catalysed diyne-cyclobutanone [4+2+2] cycloadditions,
Jia-Yuan Tao1, De-Cai Fang, Gregory A Chass
1College of Chemistry, Beijing Normal University, Beijing, 100875, China. dcfang@bnu.edu.cn.
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.
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