title: A class of ruthenium(II) catalyst for asymmetric transfer hydrogenations of ketones.
abstract: Ruthenium dimer 6 (readily available in two steps from TsDPEN) is converted directly to monomeric asymmetric transfer hydrogenation catalyst 3 in situ under the conditions employed for ketone reduction. Catalyst 3 is a significantly more active catalyst for this application than the untethered derivative, exhibits higher enantioselectivities across a range of substrates, and appears to be highly stable to the reaction conditions. It is active at loadings of as low as 0.01 mol %, and reductions at the 0.1 mol % level are complete within 20 min at 80 degrees C without significant loss of enantioselectivity.
authors.affiliation: Asymmetric Catalysis Group, Department of Chemistry, University of Warwick, UK.
authors.forename: Aidan M
authors.initials: AM
authors.lastname: Hayes
authors.forename: David J
authors.initials: DJ
authors.lastname: Morris
authors.forename: Guy J
authors.initials: GJ
authors.lastname: Clarkson
authors.forename: Martin
authors.initials: M
authors.lastname: Wills