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Updated: Mar 19, 2026
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A Two-Step Protocol for Umpolung Functionalization of Ketones Via Enolonium Species
Published on: August 16, 2018
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Potassium tert-Butoxide: Solubility, Solution Structure, and Reactivity.
Russell F Algera1, Nahian Khan1, Philipp C Roosen1
1Pfizer Chemical Research and Development, Pfizer, Inc., Groton, Connecticut 06340, United States.
The Journal of Organic Chemistry
|March 18, 2026
Summary
Potassium tert-butoxide (KOtBu) forms distinct solution structures—tetramers or monomers—depending on the solvent. This research clarifies KOtBu aggregation and reactivity, impacting its use in chemical synthesis.
Area of Science:
- Inorganic Chemistry
- Physical Chemistry
- Organic Synthesis
Background:
- Potassium tert-butoxide (KOtBu) is a widely used strong base in organic synthesis.
- Its solution behavior and aggregation state have been poorly understood, impacting reactivity.
- Previous assumptions about KOtBu deaggregation in donor solvents require re-evaluation.
Purpose of the Study:
- To elucidate the fundamental solution structures of KOtBu.
- To correlate these structures with reactivity in dehydrohalogenation reactions.
- To clarify the role of donor solvents in KOtBu aggregation and solubility.
Main Methods:
- Donor solvent titration
- Diffusion Nuclear Magnetic Resonance (NMR) spectroscopy
- Density Functional Theory (DFT) calculations
Main Results:
- KOtBu exists as unsolvated tetramers (non-Lewis basic solvents), disolvated tetramers (Lewis basic solvents), or solvated monomers (protic solvents).
- Strong aprotic donor solvents do not necessarily deaggregate the KOtBu cubic tetramer.
- A previously reported 1:1 KOtBu-tert-butanol complex exhibits poor solubility and reactivity.
Conclusions:
- The solution structure of KOtBu is dictated by solvent properties (Lewis basicity, proticity).
- Reactivity of KOtBu is enhanced by Lewis basic solvents that stabilize transition states.
- Understanding KOtBu aggregation is crucial for optimizing its application in synthesis.
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