title: The catalytic asymmetric Fischer indolization.
abstract: The first catalytic asymmetric Fischer indolization is reported. In the presence of a 5 mol % loading of a novel spirocyclic chiral phosphoric acid, 4-substituted cyclohexanone-derived phenylhydrazones undergo a highly enantioselective indolization. Efficient catalyst turnover was achieved by the addition of a weakly acidic cation exchange resin, which removes the generated ammonia. The reaction can be conducted under mild conditions and gives various 3-substituted tetrahydrocarbazoles in generally high yields.
authors: Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, D-45470 Mülheim an der Ruhr, Germany.
authors: Steffen
authors: S
authors: Müller
authors: Matthew J
authors: MJ
authors: Webber
authors: Benjamin
authors: B
authors: List