title: Synthesis of Enantioenriched Indolines by a Conjugate Addition/Asymmetric Protonation/Aza-Prins Cascade Reaction.
abstract: A conjugate addition/asymmetric protonation/aza-Prins cascade reaction has been developed for the enantioselective synthesis of fused polycyclic indolines. A catalyst system generated from ZrCl4 and 3,3'-dibromo-BINOL enables the synthesis of a range of polycyclic indolines in good yields and with high enantioselectivity. A key finding is the use of TMSCl and 2,6-dibromophenol as a stoichiometric source of HCl to facilitate catalyst turnover. This transformation is the first in which a ZrCl4 ⋅BINOL complex serves as a chiral Lewis-acid-assisted Brønsted acid.
authors: The Warren and Katharine Schlinger Laboratory of Chemistry and Chemical Engineering, Division of Chemistry and ChemicalEngineering, California Institute of Technology, Pasadena, CA 91125, USA.
authors: Blake E
authors: BE
authors: Daniels
authors: The Warren and Katharine Schlinger Laboratory of Chemistry and Chemical Engineering, Division of Chemistry and ChemicalEngineering, California Institute of Technology, Pasadena, CA 91125, USA.
authors: Jane
authors: J
authors: Ni
authors: The Warren and Katharine Schlinger Laboratory of Chemistry and Chemical Engineering, Division of Chemistry and ChemicalEngineering, California Institute of Technology, Pasadena, CA 91125, USA. reisman@caltech.edu.
authors: Sarah E
authors: SE
authors: Reisman
mesh_terms: D001372:Aza Compounds / Q000737:chemistry*; D018360:Crystallography, X-Ray; D007211:Indoles / Q000737:chemistry*; D011522:Protons; D013237:Stereoisomerism
chemical_list: D001372:Aza Compounds; D007211:Indoles; D011522:Protons; C057812:indoline
keywords: Lewis acids; cyclizations; enantioselectivity; heterocycles; zirconium