title: Enantioselective 1,3-dipolar cycloaddition of azomethine imines with propioloylpyrazoles induced by chiral π-cation catalysts.
abstract: We developed 1,3-dipolar cycloadditions of azomethine imines with propioloylpyrazoles catalyzed by a chiral copper(II) complex of 3-(2-naphthyl)-l-alanine amide. The asymmetric environment created by intramolecular π-cation interaction and the N-alkyl group of the chiral ligand gives the corresponding adducts in high yields with excellent enantioselectivity. This is the first successful method for the catalytic enantioselective 1,3-dipolar cycloaddition of azomethine imines with internal alkyne derivatives to give fully substituted pyrazolines.
authors.affiliation: Graduate School of Engineering, Nagoya University , Furo-cho, Chikusa, Nagoya 464-8603, Japan.
authors.forename: Masahiro
authors.initials: M
authors.lastname: Hori
authors.forename: Akira
authors.initials: A
authors.lastname: Sakakura
authors.forename: Kazuaki
authors.initials: K
authors.lastname: Ishihara
mesh_terms: D000409:Alanine / Q000031:analogs & derivatives; D001391:Azo Compounds / Q000737:chemistry*; D002384:Catalysis; D002412:Cations / Q000737:chemistry; D003300:Copper / Q000737:chemistry; D061565:Cycloaddition Reaction; D007097:Imines / Q000737:chemistry*; D011720:Pyrazoles / Q000737:chemistry*; D013237:Stereoisomerism; D013882:Thiosemicarbazones / Q000737:chemistry*
chemical_list: D001391:Azo Compounds; D002412:Cations; D007097:Imines; D011720:Pyrazoles; D013882:Thiosemicarbazones; C512188:azomethine; D003300:Copper; D000409:Alanine