title: Group 11 metal amide-catalyzed asymmetric cycloaddition reactions of azomethine imines with terminal alkynes.
abstract: We developed a 1,3-dipolar cycloaddition reaction of azomethine imines with terminal alkynes catalyzed by group 11 metal amides to provide N,N-bicyclic pyrazolidinone derivatives. This reaction afforded the cycloadducts in a unique 5,7-disubstituted manner. Furthermore, we succeeded in applying this catalysis to asymmetric reactions, and the desired heterocycles were produced in high yields with exclusive regioselectivity and high enantioselectivity. Mechanistic studies elucidated a stepwise reaction pathway and critical features that determine the regioselectivity.
authors.affiliation: Department of Chemistry, School of Science, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
authors.forename: Takaki
authors.initials: T
authors.lastname: Imaizumi
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Yamashita
authors.forename: Shū
authors.initials: S
authors.lastname: Kobayashi
mesh_terms: D000480:Alkynes / Q000737:chemistry*; D000577:Amides / Q000737:chemistry*; D001391:Azo Compounds / Q000737:chemistry*; D002384:Catalysis; D003500:Cyclization; D007097:Imines / Q000737:chemistry*; D015394:Molecular Structure; D009942:Organometallic Compounds / Q000737:chemistry*; D011720:Pyrazoles / Q000138:chemical synthesis* / Q000737:chemistry; D013882:Thiosemicarbazones / Q000737:chemistry*; D028561:Transition Elements / Q000737:chemistry*
chemical_list: D000480:Alkynes; D000577:Amides; D001391:Azo Compounds; D007097:Imines; D009942:Organometallic Compounds; D011720:Pyrazoles; D013882:Thiosemicarbazones; D028561:Transition Elements; C512188:azomethine