title: Chiral Metal Nanoparticle Systems as Heterogeneous Catalysts beyond Homogeneous Metal Complex Catalysts for Asymmetric Addition of Arylboronic Acids to α,β-Unsaturated Carbonyl Compounds.
abstract: We describe the use of chiral metal nanoparticle systems, as novel heterogeneous chiral catalysts for the asymmetric 1,4-addition of arylboronic acids to α,β-unsaturated carbonyl compounds, as representative C-C bond-forming reactions. The reactions proceeded smoothly to afford the corresponding β-arylated products in high to excellent yields and outstanding enantioselectivities with wide substrate scope. Remarkably, the nanoparticle catalysts showed performance in terms of yield, enantioselectivity, and catalytic turnover that was superior to that of the corresponding homogeneous metal complexes. The catalyst can be successfully recovered and reused in a gram-scale synthesis with low catalyst loading without significant loss of activity. The nature of the active species was investigated, and we found that characteristic features of the nanoparticle system were totally different from those of the metal complex system.
authors.affiliation: Department of Chemistry, School of Science, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Yasukawa
authors.affiliation: Department of Chemistry, School of Science, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
authors.forename: Aya
authors.initials: A
authors.lastname: Suzuki
authors.affiliation: Department of Chemistry, School of Science, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Miyamura
authors.affiliation: Department of Chemistry, School of Science, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
authors.forename: Kohei
authors.initials: K
authors.lastname: Nishino
authors.affiliation: Department of Chemistry, School of Science, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
authors.forename: Shū
authors.initials: S
authors.lastname: Kobayashi