Dendritic Hydrogenation Catalysts

  • Author: Theresa Kueckmann
  • Published Date: 08 April 2013
  • Source / Publisher: Chemistry – An Asian Journal/Wiley-VCH
  • Copyright: Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
thumbnail image: Dendritic Hydrogenation Catalysts

Iridium catalysts with chiral P,N-ligands catalyze asymmetric hydrogenation reactions, but catalyst dimerization and consequent deactivation is problematic. Researchers in China have used a dendritic catalyst to suppress dimerization and increase activity in the hydrogenation of benzodiazepines.

Qing-Hua Fan and co-workers, Institute of Chemistry, Chinese Academy of Sciences, Beijing, attached dendritic poly(benzyl ether) arms to a chiral phosphinooxazoline core (pictured). Complexation of the dendrimers with iridium led to an active catalyst for the asymmetric hydrogenation of 2,4-diaryl-1,5-benzodiazepines. The dendritic catalyst gave high conversion with good diastereo- and enantioselectivity and showed better catalytic performance than its small-molecule counterpart, which suffered from the formation of inactive dimers and trimers. The catalyst could be recovered easily by precipitation with hexane, although subsequent runs with the same catalyst showed lower conversion.

The positive dendritic effect holds promise for the development of related catalysts for other transformations.

Article Views: 3235

Sign in Area

Please sign in below

Additional Sign In options

Please note that to comment on an article you must be registered and logged in.
Registration is for free, you may already be registered to receive, e.g., the newsletter. When you register on this website, please ensure you view our terms and conditions. All comments are subject to moderation.

Article Comments - To add a comment please sign in

If you would like to reuse any content, in print or online, from, please contact us first for permission and consult our permisson guidance prior to making your request

Follow on Facebook Follow on Twitter Follow on YouTube Follow on LinkedIn Follow on Instagram RSS Sign up for newsletters

Magazine of Chemistry Europe (16 European Chemical Societies) published by Wiley-VCH