Duan, Z., Zhu, J., Majhi, P.K. et al. (4 more authors) (2025) Quantifying Breslow intermediate reactivity in intermolecular Stetter reactions. Chemical Science. ISSN: 2041-6520
Abstract
Quantification of the reactivity of the archetypal Breslow intermediate in NHC-mediated transformations has not been achievable to date and is regarded as a significant challenge due to multiple competitive pathways and their deconvolution. This manuscript describes the development of a kinetic approach to this challenge that avoids the influence of the competitive benzoin reaction and allows quantification of the reactivity of a Breslow intermediate derived from 2-pyridine carboxaldehyde and an in situ generated N-pentafluorophenyl substituted triazolinylidene NHC with a diverse range of Michael acceptors in the intermolecular Stetter reaction. Using this approach the pseudo first-order rate constants of >40 Michael acceptors, primarily derived from (E)-chalcones but also including a nitrolefin and malonic esters, were measured. Notably, incorporating electron-withdrawing substituents within the C(1)-aryl group of (E)-chalcones leads to a substantial enhancement in reactivity, with Hammett and Swain-Lupton analysis used to understand these observations. In addition, an unexpected additive substituent effect associated with the 4,4'-disubstitution of chalcones was observed, with DFT analysis offering insights into this intriguing phenomenon.
Metadata
| Item Type: | Article |
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| Authors/Creators: |
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| Copyright, Publisher and Additional Information: | © 2025 The Author(s). Published by the Royal Society of Chemistry. This article is licensed under a Creative Commons Attribution 3.0 Unported Licence. |
| Dates: |
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| Institution: | The University of Leeds |
| Academic Units: | The University of Leeds > Faculty of Engineering & Physical Sciences (Leeds) > School of Chemistry (Leeds) |
| Date Deposited: | 02 Oct 2025 15:13 |
| Last Modified: | 29 Oct 2025 14:34 |
| Status: | Published online |
| Publisher: | Royal Society of Chemistry |
| Identification Number: | 10.1039/d5sc05021a |
| Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:232446 |

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