title: Asymmetric α-amination of 4-substituted pyrazolones catalyzed by a chiral Gd(OTf)3/N,N'-dioxide complex: highly enantioselective synthesis of 4-amino-5-pyrazolone derivatives.
abstract: The asymmetric α-amination of 4-substituted pyrazolones with azodicarboxylates was investigated for the first time, employing an N,N'-dioxide gadolinium(III) complex as the catalyst. The novel transformations exhibited high yield, and 4-amino-5-pyrazolone derivatives bearing a chiral quaternary center were obtained in excellent yields (up to 99%) and enantioselectivities (90%-97% ee) for a broad scope of 5-pyrazolones by using 1 mol % or only 0.05 mol % of catalyst.
authors.affiliation: Key Laboratory of Green Chemistry & Technology, Ministry of Education, College of Chemistry, Sichuan University, Chengdu 610064, People's Republic of China.
authors.forename: Zhigang
authors.initials: Z
authors.lastname: Yang
authors.forename: Zhen
authors.initials: Z
authors.lastname: Wang
authors.forename: Sha
authors.initials: S
authors.lastname: Bai
authors.forename: Xiaohua
authors.initials: X
authors.lastname: Liu
authors.forename: Lili
authors.initials: L
authors.lastname: Lin
authors.forename: Xiaoming
authors.initials: X
authors.lastname: Feng
mesh_terms: D000586:Amination; D002384:Catalysis; D020650:Combinatorial Chemistry Techniques; D005682:Gadolinium / Q000737:chemistry*; D015394:Molecular Structure; D009942:Organometallic Compounds / Q000737:chemistry*; D047069:Pyrazolones / Q000138:chemical synthesis* / Q000737:chemistry; D013237:Stereoisomerism
chemical_list: D009942:Organometallic Compounds; D047069:Pyrazolones; D005682:Gadolinium