title: Gold-catalyzed three-component annulation: efficient synthesis of highly functionalized dihydropyrazoles from alkynes, hydrazines, and aldehydes or ketones.
abstract: Polysubstituted dihydropyrazoles were directly obtained by a gold-catalyzed three-component annulation. This reaction consists of a Mannich-type coupling of alkynes with N,N'-disubstituted hydrazines and aldehydes/ketones followed by intramolecular hydroamination. Cascade cyclization using 1,2-dialkynylbenzene derivatives as the alkyne component was also performed producing fused tricyclic dihydropyrazoles in good yields.
authors.affiliation: Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto 606-8501, Japan.
authors.forename: Yamato
authors.initials: Y
authors.lastname: Suzuki
authors.forename: Saori
authors.initials: S
authors.lastname: Naoe
authors.forename: Shinya
authors.initials: S
authors.lastname: Oishi
authors.forename: Nobutaka
authors.initials: N
authors.lastname: Fujii
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Ohno
mesh_terms: D000447:Aldehydes / Q000737:chemistry*; D000480:Alkynes / Q000737:chemistry*; D002384:Catalysis; D003500:Cyclization; D006046:Gold / Q000737:chemistry*; D006834:Hydrazines / Q000737:chemistry*; D006865:Hydrogenation; D007659:Ketones / Q000737:chemistry*; D015394:Molecular Structure; D011720:Pyrazoles / Q000138:chemical synthesis*
chemical_list: D000447:Aldehydes; D000480:Alkynes; D006834:Hydrazines; D007659:Ketones; D011720:Pyrazoles; D006046:Gold