Anti-Markovnikov Hydroamination of Unactivated Alkenes

  • Author:
  • Published: 17 October 2019
  • Copyright: Wiley-VCH Verlag GmbH & Co. KGaA
  • Source / Publisher: Journal of the American Chemical Society/ACS Publications
  • Associated Societies: American Chemical Society (ACS), USA
thumbnail image: Anti-Markovnikov Hydroamination of Unactivated Alkenes

Amines are commonly used in, e.g., pharmaceutical chemistry. They can, for example, be synthesized via the hydroamination of alkenes. Intermolecular hydroaminations of unactivated alkenes, however, can be challenging. In addition, existing methods for this type of reaction usually give the Markovnikov products (which are aminated at the higher-substituted carbon). Until now, there had been no general method for the intermolecular anti-Markovnikov hydroamination of unactivated alkenes with primary alkyl amines.

Robert R. Knowles, Princeton University, NJ, USA, and colleagues have developed a photocatalytic method that gives the anti-Markovnikov hydroamination products(pictured) from unactivated alkenes and primary alkyl amines. The team used [Ir(dF(CF3)ppy)2(4,4′-d(CF3)bpy)]PF6 as a photocatalyst (dF(CF3)ppy = 2-(2,4-difluorophenyl)-5-
(trifluoromethyl)pyridine; 4,4'-d(CF3)bpy =  4,4'-bis(trifluoromethyl)-2,2'-bipyridine) and 2,4,6-triisopropylbenzenethiol (TRIP thiol) as a H-atom transfer (HAT) catalyst. The reaction was performed in dioxane under a blue light-emitting diode (LED) at room temperature.

The desired products were obtained in moderate to excellent yields. The reaction provides high selectivities for the secondary over the tertiary amine products, i.e., it avoids over-alkylation. The team observed no Markovnikov addition products for all but one of the tested substrates. According to the researchers, the transformation proceeds via aminium radical cation (ARC) intermediates.


Article Views: 2291

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 permission 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