Deprotonative Coupling of Benzylic C–H Bonds with Carbonyls

  • Author: ChemistryViews.org
  • Published: 09 April 2019
  • Copyright: Wiley-VCH Verlag GmbH & Co. KGaA
  • Source / Publisher: Organic Letters/ACS Publications
  • Associated Societies: American Chemical Society (ACS), USA
thumbnail image: Deprotonative Coupling of Benzylic C–H Bonds with Carbonyls

The deprotonative functionalization of C–H bonds usually requires stoichiometric amounts of strong bases. However, this approach has issues such as air- and moisture sensitivity, poor functional group tolerance, and a requirement for low temperatures.


Masanori Shigeno, Yoshinori Kondo, and colleagues, Tohoku University, Sendai, Japan, have developed a deprotonative coupling of benzylic C(sp3)–H bonds with carbonyls (example product pictured), which is catalyzed by an amide–base system formed in situ. The team used tetramethylammonium fluoride (TMAF) and tris(trimethylsilyl)amine (N(TMS)3) to create the amide base (TMS)2N. This base can deprotonate a variety of benzylic C–H bonds. The team used different substituted arenes or heteroarenes as substrates and coupled them with a variety of ketones, non-enolizable aldehydes, or N,N-disubstituted formamides at 60 °C.


The desired products were obtained in moderate to excellent yields. The catalytic system is more effective than conventional amide bases such as potassium bis(trimethylsilyl)amide (KHMDS). The reaction works even for toluene derivatives with low reactivity.


 

Article Views: 485

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