Oxidative N-Heterocyclic Carbene Catalysis.
Carmela De Risi1, Arianna Brandolese2, Graziano Di Carmine1
1Dipartimento di Scienze Chimiche, Farmaceutiche ed Agrarie, Università di Ferrara, Via L. Borsari, 46, 44121, Ferrara, Italy.
Chemistry (Weinheim an Der Bergstrasse, Germany)
|October 7, 2022
Summary
Oxidative N-heterocyclic carbene (NHC) catalysis enables new synthetic pathways beyond traditional umpolung reactions. This review details recent advances in oxidative NHC-catalyzed transformations, focusing on key intermediates and mechanisms.
Area of Science:
- Organocatalysis
- Synthetic Organic Chemistry
- Green Chemistry
Background:
- N-heterocyclic carbene (NHC) catalysis is a well-established organocatalytic method.
- NHC catalysis typically involves umpolung processes using acyl anion equivalents.
- Oxidative conditions significantly broaden the scope and applications of NHC catalysis.
Purpose of the Study:
- To provide an updated review of oxidative N-heterocyclic carbene (NHC)-catalyzed reactions.
- To highlight key intermediates and mechanistic insights in oxidative NHC catalysis.
- To cover literature published from 2014 to the present.
Main Methods:
- Review of recent scientific literature on oxidative NHC catalysis.
- Analysis of reaction mechanisms involving Breslow-type intermediates.
- Focus on transformations utilizing external oxidants or molecular oxygen (O2/air).
Main Results:
- Oxidative NHC catalysis facilitates diverse oxidative and oxygenative transformations.
- Activation of carbon and heteroatoms enables non-umpolung reaction pathways.
- Specific manipulation of NHC-bound intermediates dictates reaction outcomes.
Conclusions:
- Oxidative NHC catalysis offers powerful strategies for novel synthetic transformations.
- Understanding key intermediates is crucial for designing new catalytic systems.
- This methodology expands the synthetic utility of NHC organocatalysts.
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