Inverting the Reactivity of Imines

  • Author:
  • Published: 30 November 2018
  • Copyright: Wiley-VCH Verlag GmbH & Co. KGaA
  • Source / Publisher: Organic Letters/ACS Publications
  • Associated Societies: American Chemical Society (ACS), USA
thumbnail image: Inverting the Reactivity of Imines

Imines (pictured left) usually act as electrophiles in organic reactions. Their reactivity can, however, be inverted, e.g., by activation with metals or deprotonation. Photoredox catalysis can also be used to activate imines, but this rarely results in nucleophilic reactivity.

Patrick J. Walsh, Nanjing Tech University, China, and University of Pennsylvania, Philadelphia, USA, and colleagues have developed a cross-coupling reaction between imines and aldehydes under photoredox catalysis in which the imines act as nucleophiles. The team used a variety of ketimines and aldehydes as reactants, N,N-dicyclohexylmethylamine (Cy2NMe) as an electron donor, [Ir(ppy)2(4,4'-tBu-bpy)]PF6 (ppy = 2-phenylpyridine, bpy = 2,2'-bipyridine) as a catalyst, and acetonitrile as a solvent.

The desired coupling products, amino alcohols, were obtained in good to excellent yields under blue-light irradiation. The researchers propose a reaction mechanism in which Cy2NMe is oxidized by the iridium catalyst to form a radical cation. This radical activates the ketimine, which is reduced by the catalyst to give a carbanion. This carbanion can, in turn, attack the aldehyde in a nucleophilic addition and form the desired new C–C bond.


Article Views: 1431

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. more

CONNECT: on Facebook on Twitter on YouTube on LinkedIn Sign up for our free newsletter

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