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Phosphorane-Promoted C-C Coupling during Aryne Annulations
Paul V Kevorkian1, Dorian S Sneddon1, Casey B Ritts1
1Department of Chemistry, University of Minnesota, 207 Pleasant St. SE, Minneapolis, MN 55455, USA.
Angewandte Chemie (International Ed. in English)
|February 7, 2024
Summary
Arynes react with phosphoranes to form novel helical polycyclic aromatic compounds. This study details new synthetic routes and confirms structures using advanced computational and crystallographic methods.
Area of Science:
- Organic Chemistry
- Synthetic Chemistry
- Polycyclic Aromatic Hydrocarbons
Background:
- Arynes are highly reactive intermediates known for complex trapping reactions.
- Their unique electrophilicity can lead to unexpected reaction pathways.
- Formation of polycyclic aromatic compounds often involves intricate mechanisms.
Purpose of the Study:
- To investigate the reaction of thermally generated arynes with phosphoranes.
- To synthesize and characterize novel helical dibenzothiophenes and -selenophenes.
- To elucidate the mechanism of this unique transformation.
Main Methods:
- Thermal generation of arynes.
- Reaction of arynes with phosphoranes.
- DP4+ computational analysis for structural elucidation.
- X-ray crystallography for structural confirmation.
- Density Functional Theory (DFT) computations for mechanistic studies.
Main Results:
- Successful synthesis of multiple new helical polycyclic aromatic products.
- Confirmation of product structures using DP4+ and X-ray crystallography.
- Demonstration of DP4+ utility in distinguishing isomeric polycyclic aromatic compounds.
- Identification of ligand coupling (reductive elimination) as the key mechanistic step.
Conclusions:
- Thermally generated arynes react with phosphoranes to yield helical dibenzothiophenes and -selenophenes.
- DP4+ and X-ray crystallography are effective tools for structural determination of complex polycyclic aromatics.
- A plausible mechanism involving reductive elimination from a hypervalent phosphorane intermediate has been proposed.
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