Issue 35, 2022

Iron-catalysed alkene and heteroarene H/D exchange by reversible protonation of iron-hydride intermediates

Abstract

C–H functionalisation reactions offer a sustainable method for molecular construction and diversification. These reactions however remain dominated by precious metal catalysis. While significant interest in iron-catalysed C–H activation reactions has emerged, the isolation, characterisation and mechanistic understanding of these processes remain lacking. Herein the iron-catalysed C(sp2)–H bond hydrogen/deuterium exchange reaction using CD3OD is reported for both heterocycles and, for the first time, alkenes (38 examples). Isolation and characterisation, including by single-crystal X-ray diffraction, of the key iron-aryl and iron-alkenyl C–H metallation intermediates provided evidence for a reversible protonation of the active iron hydride catalyst. Good chemoselectivity was observed for both substrate classes. The developed procedure is orthogonal to previous iron-catalysed H/D exchange methods which used C6D6, D2, or D2O as the deuterium source, and uses only bench-stable reagents, including the iron(II) pre-catalyst. Further, a new mechanism of iron-hydride formation is reported in which β-hydride elimination from an alcohol generates the iron hydride. The ability to produce, isolate and characterise the organometallic products arising from C–H activation presents a basis for future discovery and development.

Graphical abstract: Iron-catalysed alkene and heteroarene H/D exchange by reversible protonation of iron-hydride intermediates

Supplementary files

Article information

Article type
Edge Article
Submitted
07 iyl 2022
Accepted
08 avq 2022
First published
11 avq 2022
This article is Open Access

All publication charges for this article have been paid for by the Royal Society of Chemistry
Creative Commons BY-NC license

Chem. Sci., 2022,13, 10291-10298

Iron-catalysed alkene and heteroarene H/D exchange by reversible protonation of iron-hydride intermediates

L. Britton, J. H. Docherty, J. Sklyaruk, J. Cooney, G. S. Nichol, A. P. Dominey and S. P. Thomas, Chem. Sci., 2022, 13, 10291 DOI: 10.1039/D2SC03802A

This article is licensed under a Creative Commons Attribution-NonCommercial 3.0 Unported Licence. You can use material from this article in other publications, without requesting further permission from the RSC, provided that the correct acknowledgement is given and it is not used for commercial purposes.

To request permission to reproduce material from this article in a commercial publication, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party commercial publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements