title: Organocatalyzed cascade aza-Michael/Michael addition for the asymmetric construction of highly functionalized spiropyrazolone tetrahydroquinolines.
abstract: An organocatalyzed diastereo- and enantioselective cascade aza-Michael/Michael addition of 2-tosylaminoenones to unsaturated pyrazolones has been developed to afford novel chiral spiropyrazolone tetrahydroquinolines containing three contiguous stereocenters. This cascade reaction proceeded well with 2 mol% chiral bifunctional tertiary amine squaramide catalyst to give the desired products in excellent yields (up to 99%) with excellent diastereoselectivity (up to >25:1 diastereomeric ratio) and high enantioselectivity (up to 91% enantiomeric excess).
authors.affiliation: School of Chemical Engineering and Environment, Beijing Institute of Technology, 5 South Zhongguancun Street, Beijing 100081 (P.R. China), Tel: (+86) 10-68914985.
authors.forename: Jun-Hua
authors.initials: JH
authors.lastname: Li
authors.forename: Da-Ming
authors.initials: DM
authors.lastname: Du
mesh_terms: D001372:Aza Compounds / Q000737:chemistry*; D002384:Catalysis; D018360:Crystallography, X-Ray; D008968:Molecular Conformation; D047069:Pyrazolones / Q000737:chemistry*; D011804:Quinolines / Q000737:chemistry*; D013141:Spiro Compounds / Q000737:chemistry*; D013237:Stereoisomerism
chemical_list: D001372:Aza Compounds; D047069:Pyrazolones; D011804:Quinolines; D013141:Spiro Compounds; C542964:1,2,3,4-tetrahydroquinoline
keywords: Michael addition; asymmetric synthesis; domino reactions; heterocycles; organocatalysis