Mechanistic investigation of [Co₂ (CO)₈] catalyzed photoaminocarbonylation
File(s)
Published version
Author(s)
Bailey, Rowan M
Schaefer, Bernd
Crimmin, Mark R
Miller, Philip W
Type
Journal Article
Abstract
Recent advances in cobalt-photocatalyzed carbonylation methods offer an efficient synthetic route to a range of amides and esters. Although preliminary studies provide important mechanistic insights, the kinetics of these reactions have not been studied in detail. Herein, we report an in-depth mechanistic investigation into the [Co2(CO)8]-catalyzed aminocarbonylation of aryl halides. Rarely used 59Co NMR spectroscopy provided evidence for [Co(CO)4]− as an on-cycle catalytic intermediate. Orders in reagents, Hammett analysis, and Eyring analysis gave unique insight into both photon-limited and photon-unlimited regimes. Data strongly suggested that the turnover-limiting step of catalysis is the reaction of [Co(CO)4]− with the aryl bromide. Plausible mechanisms for this step were considered and differentiated by experimental data, including quantum yield measurements, radical probes, and competition experiments. It is concluded that this step most likely occurs through a light-promoted nucleophilic attack of the cobalt anion on the aryl bromide. In turn, this knowledge was used to expand catalysis to more challenging reagents such as aryl chlorides, low nucleophilicity amines, and acyclic vinyl halides. Enhanced catalyst efficiency (TON and TOF improved >10-fold) was also achieved for established substrates, strengthening the industrial use case of this technology.
Date Issued
2026-07-01
Date Acceptance
2026-06-05
Citation
Journal of the American Chemical Society, 2026, 148 (25), pp.25905-25915
ISSN
0002-7863
Publisher
American Chemical Society (ACS)
Start Page
25905
End Page
25915
Journal / Book Title
Journal of the American Chemical Society
Volume
148
Issue
25
Copyright Statement
© 2026 The Authors. Published by American Chemical Society. This publication is licensed under CC-BY 4.0 .
License URL
Identifier
10.1021/jacs.6c04362
Publication Status
Published
Date Publish Online
2026-06-18