title: Catalytic asymmetric endo-selective [3+2] cycloaddition reactions of Schiff bases of α-aminophosphonates with olefins using chiral metal amides.
abstract: Catalytic asymmetric endo-selective [3+2] cycloaddition reactions of Schiff bases of α-aminophosphonates with olefins are described. While the efficient asymmetric synthesis of several phosphonate analogues of proline derivatives is important in bioorganic chemistry, a direct catalytic method to prepare optically active endo [3+2] cycloadducts of α-aminophosphonates with olefins has never been developed. We found for the first time that catalyst systems prepared from Group 11 metal amides with the (R)-FeSulphos ligand were effective for the asymmetric endo-selective [3+2] cycloaddition to afford the desired proline phosphonate analogues in high yields with high endo- and high enantioselectivities.
authors.affiliation: Department of Chemistry, School of Science, The University of Tokyo Hongo, Bunkyo-ku, Tokyo, Japan. shu_kobayashi@chem.s.u-tokyo.ac.jp.
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Yamashita
authors.affiliation: Department of Chemistry, School of Science, The University of Tokyo Hongo, Bunkyo-ku, Tokyo, Japan. shu_kobayashi@chem.s.u-tokyo.ac.jp.
authors.forename: Liang Cheng
authors.initials: LC
authors.lastname: Nam
authors.affiliation: Department of Chemistry, School of Science, The University of Tokyo Hongo, Bunkyo-ku, Tokyo, Japan. shu_kobayashi@chem.s.u-tokyo.ac.jp.
authors.forename: Mark J
authors.initials: MJ
authors.lastname: Dutton
authors.affiliation: Department of Chemistry, School of Science, The University of Tokyo Hongo, Bunkyo-ku, Tokyo, Japan. shu_kobayashi@chem.s.u-tokyo.ac.jp.
authors.forename: Susumu
authors.initials: S
authors.lastname: Yoshimoto
authors.affiliation: Department of Chemistry, School of Science, The University of Tokyo Hongo, Bunkyo-ku, Tokyo, Japan. shu_kobayashi@chem.s.u-tokyo.ac.jp.
authors.forename: Shū
authors.initials: S
authors.lastname: Kobayashi