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Updated: Jul 16, 2026
09:54
Chemoselective Preparation of 1-Iodoalkynes, 1,2-Diiodoalkenes, and 1,1,2-Triiodoalkenes Based on the Oxidative Iodination of Terminal Alkynes
Published on: September 12, 2018
Stoichiometric and catalytic oxidations with hypervalent organo-lambda3-iodanes.
1Graduate School of Pharmaceutical Sciences, University of Tokushima, 1-78 Shomachi, Tokushima 770-8505, Japan.
Chemical Record (New York, N.Y.)
|February 17, 2007
Summary
Researchers developed stable, reactive hypervalent iodine complexes using 18-crown-6 for mild oxidation reactions. These complexes efficiently oxidize various functional groups and catalyze ketone alpha-oxidation, showcasing their versatility in organic synthesis.
Area of Science:
- Hypervalent Iodine Chemistry
- Organic Synthesis
- Crown Ether Complexes
Background:
- Iodosylbenzene derivatives are potent oxidants but often require careful handling.
- Crown ethers can stabilize reactive species through complexation.
- Mild and versatile oxidation methods are crucial for modern organic synthesis.
Purpose of the Study:
- To isolate and characterize novel, stabilized iodosylbenzene complexes with 18-crown-6.
- To explore the reactivity and utility of these complexes as oxidants in organic transformations.
- To investigate the catalytic alpha-oxidation of ketones using hypervalent iodine species.
Main Methods:
- Synthesis of hydroxy(phenyl)iodonium ion complexes with 18-crown-6 (e.g., PhI(OH)BF(4).18C6).
- X-ray crystallography for structural elucidation of the stabilized complexes.
- Stoichiometric oxidation reactions of various functional groups (olefins, sulfides, phenols, etc.) and catalytic alpha-oxidation of ketones.
Main Results:
- Stable, crystalline complexes of activated iodosylbenzene with 18-crown-6 were successfully prepared and characterized.
- X-ray analysis confirmed the stabilizing role of 18-crown-6 through interactions with the iodine(III) center.
- The complexes demonstrated high reactivity as versatile oxidants under mild conditions, particularly in aqueous media, and enabled efficient catalytic alpha-acetoxylation of ketones.
Conclusions:
- Crown ether complexation significantly enhances the stability of hypervalent iodine oxidants.
- These stabilized complexes serve as effective and versatile reagents for a broad range of oxidative transformations.
- The study highlights a novel approach to catalytic ketone oxidation using in situ generated hypervalent iodine species.
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