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Synthesis of Hypervalent Iodonium Alkynyl Triflates for the Application of Generating Cyanocarbenes
Published on: September 8, 2013
Cyanogen formation during asymmetric cyanohydrin synthesis
Victor Chechik1, Marco Conte, Trevor Dransfield
1Department of Chemistry, University of York, Heslington, York, UK YO10 5DD. vc4@york.ac.uk
Chemical Communications (Cambridge, England)
|May 6, 2010
Summary
Vanadium(V) catalysts are reduced to vanadium(IV) during asymmetric cyanohydrin synthesis. This reduction is caused by cyanide, which oxidizes to cyanogen through a non-radical pathway.
Area of Science:
- Organometallic chemistry
- Catalysis
- Asymmetric synthesis
Background:
- Vanadium(V)oxo(salen) complexes are effective catalysts for asymmetric cyanohydrin synthesis.
- Understanding the catalytic cycle, including redox processes, is crucial for optimizing these reactions.
Purpose of the Study:
- To investigate the redox behavior of vanadium(V)oxo(salen) catalysts during asymmetric cyanohydrin synthesis.
- To identify the reducing agent and elucidate the oxidation mechanism of cyanide.
Main Methods:
- Electron Paramagnetic Resonance (EPR) spectroscopy was used to monitor the oxidation state of the vanadium catalyst.
- Kinetic studies were performed to understand the reaction mechanism.
Main Results:
- The vanadium(V)oxo(salen) catalyst is reduced to vanadium(IV)oxo(salen) during the reaction.
- Cyanide acts as the reducing agent, being oxidized to cyanogen.
- The oxidation of cyanide proceeds via a non-radical mechanism.
Conclusions:
- The catalytic cycle involves a redox transformation of the vanadium complex.
- Cyanide plays a dual role as a nucleophile and a reducing agent.
- The non-radical oxidation of cyanide is a key step in the catalytic process.
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