Hemilabile Amidomonophosphine Ligand−Rhodium(I) Complex-Catalyzed Asymmetric 1,4-Addition of Arylboronic Acids to Cycloalkenones
journal contributionposted on 2002-07-09, 00:00 authored by Masami Kuriyama, Kazushige Nagai, Ken-ichi Yamada, Yoshinao Miwa, Tooru Taga, Kiyoshi Tomioka
The asymmetric 1,4-addition reaction of arylboronic acids with cycloalkenones was catalyzed by 1 mol % of an amidomonophosphine−rhodium(I) catalyst in a 10:1 mixture of 1,4-dioxane and water at 100 °C, affording 3-arylcycloalkanones in reasonably high enantioselectivity and high yields. It was revealed by NMR, IR, and X-ray spectroscopies that this bidentate amidomonophosphine behaves as a hemilabile ligand that contains a hard donor site in addition to the soft donor in a molecule. Phosphorus atom strongly bonds to rhodium(I), and the amide carbonyl oxygen is coordinatively labile. The reaction efficacy of phenylboronic acid with cyclopent-2-en-1-one was significantly dependent on the possibility of coordination of the amide carbonyl oxygen to rhodium(I).
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enantioselectivityarylboronic acidsLigandAmidomonophosphinephenylboronic acidmixturehemilabile liganddioxaneAsymmetriccoordinationrhodiumcyclopentArylboronic Acidsarylcycloalkanonedonor siteIRmoleculeamide carbonyl oxygenCycloalkenonecatalystspectroscopiemolPhosphorus atomreaction efficacybidentate amidomonophosphineNMRyieldcycloalkenonecoordinativelyHemilabilebond