title: Enantioselective synthesis of dihydropyrazoles by formal [4+1] cycloaddition of in situ-derived azoalkenes and sulfur ylides.
abstract: An unprecedented strategy to access highly enantioenriched dihydropyrazoles is described. It involves formal [4+1] cycloadditions of in situ-derived azoalkenes and sulfur ylides catalyzed by a chiral copper/Tol-BINAP complex. A variety of synthetically and biologically important dihydropyrazoles have been obtained with high enantioselectivities (up to 97:3 er) in good yields (83-97%).
authors.affiliation: Key Laboratory of Pesticide & Chemical Biology, Ministry of Education, College of Chemistry, Central China Normal University, 152 Luoyu Road, Wuhan, Hubei 430079, China.
authors.forename: Jia-Rong
authors.initials: JR
authors.lastname: Chen
authors.forename: Wan-Rong
authors.initials: WR
authors.lastname: Dong
authors.forename: Mathieu
authors.initials: M
authors.lastname: Candy
authors.forename: Fang-Fang
authors.initials: FF
authors.lastname: Pan
authors.forename: Manuel
authors.initials: M
authors.lastname: Jörres
authors.forename: Carsten
authors.initials: C
authors.lastname: Bolm
mesh_terms: D000475:Alkenes / Q000737:chemistry*; D001391:Azo Compounds / Q000737:chemistry*; D002384:Catalysis; D018360:Crystallography, X-Ray; D003500:Cyclization; D008958:Models, Molecular; D015394:Molecular Structure; D009942:Organometallic Compounds / Q000737:chemistry; D011720:Pyrazoles / Q000138:chemical synthesis* / Q000737:chemistry; D013237:Stereoisomerism; D013455:Sulfur / Q000737:chemistry*
chemical_list: D000475:Alkenes; D001391:Azo Compounds; D009942:Organometallic Compounds; D011720:Pyrazoles; D013455:Sulfur