title: Zirconium-catalyzed enantioselective [3+2] cycloaddition of hydrazones to olefins leading to optically active pyrazolidine, pyrazoline, and 1,3-diamine derivatives.
abstract: Asymmetric [3+2] cycloaddition of hydrazones to external olefins has been successfully conducted in high yields with high enantioselectivities using a chiral zirconium catalyst. These reactions open ways to synthetically and biologically important pyrazoline, pyrazolidine, and 1,3-diamine derivatives. Further, several experiments suggested that the reactions proceeded via concerted pathways.
authors.affiliation: Graduate School of Pharmaceutical Sciences, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Yamashita
authors.forename: Shū
authors.initials: S
authors.lastname: Kobayashi