title: Synthesis of a new chiral bisphospholane ligand for the Rh(I)-catalyzed enantioselective hydrogenation of isomeric beta-acylamido acrylates.
abstract: The highly stereoselective synthesis of a chiral silylphospholane has been described, which can be advantageously used as a building block under base-free conditions for the construction of diphosphines related to DuPHOS. The utility of silylphospholane is shown in the synthesis of a new bisphospholane ligand 1 (MalPHOS), which is characterized by a maleic anhydride backbone. The ligand forms with Rh(I) a complex with a larger bite angle P-Rh-P than the analogue Me-DuPHOS complex. Both complexes have been tested in the asymmetric hydrogenation of unsaturated alpha- and beta-amino acid precursors of pharmaceutical relevance. In several cases, the new catalyst was superior in comparison to the Me-DuPHOS complex, in particular when (Z)-configured beta-acylamido acrylates were used as substrates.
authors.affiliation: Institut für Organische Katalyseforschung an der Universität Rostock e.V., Buchbinderstr. 5/6, 18055 Rostock, Germany. jens.holz@ifok.uni-rostock.de
authors.forename: Jens
authors.initials: J
authors.lastname: Holz
authors.forename: Axel
authors.initials: A
authors.lastname: Monsees
authors.forename: Haijun
authors.initials: H
authors.lastname: Jiao
authors.forename: Jinsong
authors.initials: J
authors.lastname: You
authors.forename: Igor V
authors.initials: IV
authors.lastname: Komarov
authors.forename: Christine
authors.initials: C
authors.lastname: Fischer
authors.forename: Karlheinz
authors.initials: K
authors.lastname: Drauz
authors.forename: Armin
authors.initials: A
authors.lastname: Börner