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A Microwave-Assisted Direct Heteroarylation of Ketones Using Transition Metal Catalysis
Published on: February 16, 2020
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Ketonization of incarcerated acetophenone enol
Darren A Makeiff1, Kodumuru Vishnumurthy, John C Sherman
1Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, BC Canada V6T 1Z1.
Journal of the American Chemical Society
|August 9, 2003
Summary
Simple enols were generated in a carceplex, showing extremely slow ketonization rates compared to solutions. Water within the carceplex is essential for the reaction mechanism, while acids or bases inhibit it.
Area of Science:
- Supramolecular Chemistry
- Organic Chemistry
- Physical Chemistry
Background:
- Enols are reactive intermediates crucial in organic chemistry.
- Understanding enol reactivity within confined environments is key to controlling chemical processes.
- Carceplexes offer unique microenvironments for studying molecular behavior.
Purpose of the Study:
- To generate and study a free-standing simple enol within a carceplex.
- To determine the rates of ketonization under various conditions.
- To elucidate the mechanism of ketonization within the carceplex environment.
Main Methods:
- Generation of a free-standing simple enol within a carceplex.
- Kinetic studies of ketonization under varied conditions (e.g., presence of water, acid, base).
- Spectroscopic analysis to monitor reaction intermediates and products.
Main Results:
- Ketonization of the complexed enol is significantly slower than in solution.
- The presence of complexed water is essential for the ketonization mechanism.
- The mechanism involves enolate formation and subsequent protonation by the same water molecule.
- Acids and bases inhibit ketonization by sequestering water from the carceplex cavity.
Conclusions:
- Carceplexes dramatically alter enol reactivity, slowing down ketonization.
- Water plays a dual role in the proposed ketonization mechanism within the carceplex.
- External acids or bases disrupt the necessary water environment, inhibiting the reaction.
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