Hannedouche Jérôme, Clarkson Guy J, Wills Martin
Asymmetric Catalysis Group, Department of Chemistry, University of Warwick, Coventry, CV4 7AL.
J Am Chem Soc. 2004 Feb 4;126(4):986-7. doi: 10.1021/ja0392768.
Ruthenium dimer 4 is converted directly to monomeric asymmetric transfer hydrogenation catalyst 2 under the conditions employed for ketone reduction. Using 0.25 mol % of either 4 or 0.5 mol % of 2 in formic acid/triethylamine, it is possible to achieve ketone reduction in quantitative conversion and with ee's as high as 98%. Complex 2 is a robust "single-reagent" catalyst which offers significant scope for modification toward specific substrates. The synthesis and applications of an analogous complex derived from (1R,2S)-norephedrine are also described.
