NHC2Breslow · Mechanistic Studies of NHC Organocatalysis – Quantifying the Reactivity of the Breslow Intermediate
Horizon 2020 — Marie Skłodowska-Curie Actions
- Duration
- 2022-03-01 → 2024-02-29
- EU contribution
- €212,934
- Participants
- 1
- Scheme
- MSCA-IF
Lines connect the coordinator with its partners.
Results in brief
Mechanistic Studies of NHC Organocatalysis – Quantifying the Reactivity of the Breslow Intermediate
The main aim of this proposal was to generate a quantitative understanding of the behaviour of the so called Breslow Intermediate that has been implicated in NHC based catalysis. This proposal aimed to deliver quantitative underpinning knowledge of this key intermediate that could (i) be used to develop a fundamental scale to quantify BI reactivity with a range of electrophilic species and (ii) be applied to answer unresolved mechanistic and chemoselectivity questions in contemporary NHC-based catalysis. Work in this project has achieved - for the first time - a novel kinetic approach othat allows the relative quantification and reactivity of diverse Michael acceptors when they interact with the presumed N-C6F5 Breslow intermediate in the intermolecular Stetter reaction. This encompasses all workpackages WP1-WP6 and goes beyond the current state-of-the-art. The new synthetic methods developed that use catalytic quantities of non-toxic organocatalysts to generate new chiral organic materials address issues relating to sustainability. Futhermore the mechanistic insight generated will be of widespread interest to the synthetic community and industry and so may longer term have significant benefits for society. Potential users of the project results are other academic groups around the world alongside industry who recognise the mechanistic insight provided.
Data: CORDIS, © European Union
Project objective
N-heterocyclic carbenes (NHCs) are the most versatile class of organocatalyst, allowing access to a variety of catalytic intermediates for the construction of complex targets from simple starting materials under mild conditions. Despite many individual conceptual advances in this field, it is not understood (or even commonly acknowledged by practitioners) why product distributions of NHC-catalysed processes often differ dramatically with catalyst scaffold or with subtle substituent variation within an NHC-catalyst family. Following the many synthetic innovations over the past decade, future transformative benefits will rely on the careful, quantitative and detailed analysis and understanding of all aspects of reactions mechanisms in order to make informed choice of catalyst for a given transformation, rather then relying on brute force screening. To break from this traditional, time-intensive screening approach and fully realize the potential of NHCs, a quantitative mechanistic understanding is required. Central to this state-of-the-art field is the catalytically competent “Breslow intermediate” (BI) that is regarded as the cornerstone of modern NHC-mediated catalysis. First characterised in 2012, its reactivity is key to a multitude of synthetic transformations. Despite its importance, a quantitative understanding of the behaviour of this transiently formed species has yet to be defined. This proposal will deliver quantitative underpinning knowledge of this key intermediate that will (i) be used to develop a fundamental scale to quantify BI reactivity with a range of electrophilic species and (ii) be applied to answer unresolved mechanistic and chemoselectivity questions in contemporary NHC-based catalysis.
Original text from CORDIS.
Participants
- THE UNIVERSITY COURT OF THE UNIVERSITY OF ST ANDREWS · ST ANDREWSCoordinatorUnited Kingdom
Links
Data: CORDIS, © European Union