Semireduction of Alkynes

  • Author: Vikki Cantrill
  • Published: 05 March 2013
  • Copyright: Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
  • Source / Publisher: Organic Letters/ACS Publications
thumbnail image: Semireduction of Alkynes

The semireduction of alkynes to alkenes is an important synthetic transformation. General catalysts, e.g., Lindlar and P2 nickel, are often non-specific, resulting in isomerization or over-reduction to the alkane; and specific catalysts tend to be scope limited. Therefore, a general method for specific semireduction is needed.


Aaron Whittaker and Gojko Lalic, University of Washington, USA, have developed a copper catalyst system, which uses a copper alkoxide with a bulky IPr ligand (1,3-bis-(2,6-diisopropylphenyl)imidazol-2-ylidene) attached, polymethylhydrosiloxane, and isobutyl alcohol. The mechanism involves copper hydride formation, followed by hydrocupration of the alkyne and protonation of the alkenyl-copper intermediate to form the desired product.

This system benefits from readily-available starting materials, low catalyst loading (0.5 mol-%), low temperatures (25–45 °C), short reaction times (1 h) and excellent chemoselectivity, and works for both internal and terminal alkynes in the presence of many functional groups, including nitroarenes and aryl halides.


Article Views: 2855

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

Bookmark and Share

If you would like to reuse any content, in print or online, from ChemistryViews.org, please contact us first for permission. more


CONNECT:

ChemistryViews.org on Facebook

ChemistryViews.org on Twitter ChemistryViews.org on YouTube ChemistryViews.org on LinkedIn Sign up for our free newsletter


A product of ChemPubSoc Europe (16 European Chemical Societies)and Wiley-VCH