title: Asymmetric Three-Component Coupling Reaction of Alkyne, Enone, and Aldehyde Catalyzed by Chiral Phebox Ruthenium Catalysts.
abstract: Catalytic asymmetric three-component coupling reactions of terminal alkynes, α,β-unsaturated ketones, and aldehydes were studied. The chiral ruthenium complexes containing bis(oxazolinyl)phenyl ligands were found to serve as efficient catalysts for a tandem reaction based on conjugate addition of terminal alkynes to α,β-unsaturated ketones and subsequent aldol reaction with aldehydes, giving β-hydroxyketone derivatives containing α-propargyl groups in high yields with moderate to good enantioselectivities. This method can produce various functional molecules from commercially available substrates in a one-pot procedure. The absolute configuration of the major product was determined by X-ray analysis. The control experiments suggested that a ruthenium enolate species generated in situ by conjugate addition could be involved as an intermediate for the aldol coupling with an aldehyde.
authors.affiliation: Department of Applied Chemistry, Graduate School of Engineering, Nagoya University , Furo-cho Chikusa-ku, Nagoya 464-8603, Japan.
authors.forename: Shino
authors.initials: S
authors.lastname: Ubukata
authors.affiliation: Department of Applied Chemistry, Graduate School of Engineering, Nagoya University , Furo-cho Chikusa-ku, Nagoya 464-8603, Japan.
authors.forename: Jun-ichi
authors.initials: J
authors.lastname: Ito
authors.affiliation: Department of Applied Chemistry, Graduate School of Engineering, Nagoya University , Furo-cho Chikusa-ku, Nagoya 464-8603, Japan.
authors.forename: Ryota
authors.initials: R
authors.lastname: Oguri
authors.affiliation: Department of Applied Chemistry, Graduate School of Engineering, Nagoya University , Furo-cho Chikusa-ku, Nagoya 464-8603, Japan.
authors.forename: Hisao
authors.initials: H
authors.lastname: Nishiyama