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Measurement of Ultrafast Vibrational Coherences in Polyatomic Radical Cations with Strong-Field Adiabatic Ionization
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Structure and Reactivity of Aromatic Radical Cations Generated by FeCl3
Takahiro Horibe1, Shuhei Ohmura1, Kazuaki Ishihara1
1Graduate School of Engineering , Nagoya University , B2-3(611), Furo-cho , Chikusa, Nagoya 464-8603 , Japan.
Journal of the American Chemical Society
|January 25, 2019
Summary
This study details the creation of aromatic radical cations using iron(III) chloride (FeCl3). These cations efficiently initiate cycloaddition reactions, demonstrating a scalable and highly active catalytic process.
Area of Science:
- Organic Chemistry
- Catalysis
- Materials Science
Background:
- Aromatic radical cations are reactive intermediates with potential in organic synthesis.
- Efficient generation methods are crucial for their practical application.
- Iron(III) chloride (FeCl3) is a common Lewis acid catalyst.
Purpose of the Study:
- To isolate and characterize an aromatic radical cation generated by FeCl3.
- To elucidate the mechanism of radical cation generation.
- To explore the utility of this radical cation in cycloaddition reactions.
Main Methods:
- X-ray crystallographic analysis to determine solid-state structure.
- Kinetic studies to understand reaction mechanisms.
- Radical cation-induced cycloaddition reactions using trans-anethole.
Main Results:
- Isolation and characterization of an aromatic radical cation-FeCl4- ion pair.
- Elucidation of the generation mechanism via crystallographic and kinetic data.
- Demonstration of FeCl3-catalyzed [4+2] and [2+2] cycloadditions with broad substrate scope.
- Successful 100 g-scale reaction using 1 mol% FeCl3.
Conclusions:
- FeCl3 efficiently generates aromatic radical cations in a tight ion pair with FeCl4-.
- This system serves as a simple, highly active, and scalable catalyst for radical cation-induced cycloadditions.
- The methodology offers a versatile approach to constructing complex cyclic molecules.
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