title: Copper- and Silver-Catalyzed Diastereo- and Enantioselective Conjugate Addition Reaction of 1-Pyrroline Esters to Nitroalkenes: Diastereoselectivity Switch by Chiral Metal Complexes.
abstract: syn-Diastereoselective conjugate addition of 1-pyrroline esters to nitroalkenes in good yields with an excellent enantioselectivity by using CuOAc/Me-FcPHOX catalyst in the presence of pyridine. In contrast, AgOAc/tBu-ThioClickFerrophos catalyzed the anti diastereoselective conjugate addition with a high enantioselectivity without additional base. Thus, the preparation of chiral 1-pyrroline derivatives bearing diverse stereochemistry could be achieved. The diastereoselective reduction of the imine group in the conjugate adduct could afford the 2,5-cis-proline ester derivative.
authors.affiliation: Department of Applied Chemistry, Institute of Science and Engineering, Chuo University , Tokyo 112-8551, Japan.
authors.forename: Akihiro
authors.initials: A
authors.lastname: Koizumi
authors.affiliation: Department of Applied Chemistry, Institute of Science and Engineering, Chuo University , Tokyo 112-8551, Japan.
authors.forename: Midori
authors.initials: M
authors.lastname: Kimura
authors.affiliation: Department of Applied Chemistry, Institute of Science and Engineering, Chuo University , Tokyo 112-8551, Japan.
authors.forename: Yuri
authors.initials: Y
authors.lastname: Arai
authors.affiliation: Department of Applied Chemistry, Institute of Science and Engineering, Chuo University , Tokyo 112-8551, Japan.
authors.forename: Yuichiro
authors.initials: Y
authors.lastname: Tokoro
authors.affiliation: Department of Applied Chemistry, Institute of Science and Engineering, Chuo University , Tokyo 112-8551, Japan.
authors.forename: Shin-ichi
authors.initials: S
authors.lastname: Fukuzawa