title: Highly enantioselective synthesis of 3-amino-2-oxindole derivatives: catalytic asymmetric alpha-amination of 3-substituted 2-oxindoles with a chiral scandium complex.
abstract: A highly enantioselective alpha-amination of 3-substituted oxindoles with azodicarboxylates catalyzed by a chiral Sc(OTf)(3)/N,N'-dioxide complex (Tf: triflate) has been developed and affords the corresponding 3-amino-2-oxindole derivatives in high yields (up to 98%) with excellent enantioselectivities (up to 99% ee). The procedure is capable of tolerating a relatively wide range of substrates, and excellent results (92-96% ee) can also be obtained, even in the presence of 0.5 mol % of catalyst loading under mild conditions. These results showed the potential value of the catalytic approach. Moreover, with high synthetic versatility, the product could be easily transformed into optically active 3-amino-3-methyloxindole bearing a chiral quaternary stereogenic center.
authors.affiliation: Key Laboratory of Green Chemistry & Technology, Ministry of Education, College of Chemistry, Sichuan University, Chengdu 610064, PR 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: Ke
authors.initials: K
authors.lastname: Shen
authors.forename: Donghui
authors.initials: D
authors.lastname: Chen
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; D018360:Crystallography, X-Ray; D007211:Indoles / Q000138:chemical synthesis* / Q000737:chemistry*; D008958:Models, Molecular; D015394:Molecular Structure; D009942:Organometallic Compounds / Q000737:chemistry*; D000078183:Oxindoles; D012538:Scandium / Q000737:chemistry*; D013237:Stereoisomerism
chemical_list: C551521:3-amino-2-oxindole; D007211:Indoles; D009942:Organometallic Compounds; D000078183:Oxindoles; C022960:2-oxindole; D012538:Scandium