Powerful fluoroalkoxy molybdenum(V) reagent for selective oxidative arene coupling reaction

Area of Science:

• Organometallic Chemistry
• Synthetic Organic Chemistry
• Catalysis

Background:

• Oxidative coupling reactions are crucial for synthesizing complex organic molecules.
• Existing reagents like molybdenum pentachloride (MoCl5) often suffer from low selectivity and side reactions.
• There is a need for more efficient and selective reagents in oxidative coupling.

Purpose of the Study:

• To introduce and characterize a novel fluoroalkoxy molybdenum(V) reagent.
• To evaluate its performance in oxidative coupling reactions of aryls.
• To compare its reactivity and selectivity against established reagents.

Main Methods:

• Synthesis and characterization of the fluoroalkoxy molybdenum(V) reagent.
• Experimental investigation of oxidative coupling reactions using the new reagent.
• Theoretical calculations (DFT) to elucidate the reaction mechanism.
• Electron Paramagnetic Resonance (EPR) spectroscopy and electrochemical studies.
• X-ray diffraction analysis for structural determination.

Main Results:

• The novel fluoroalkoxy molybdenum(V) reagent demonstrates superior reactivity and selectivity compared to MoCl5 and MoCl5/TiCl4 mixtures.
• Side reactions, including chlorination and oligomer formation, are significantly minimized.
• Theoretical and experimental data support an inner-sphere electron transfer followed by a radical cation pathway.
• Structural and spectroscopic studies provide a consistent mechanistic picture.

Conclusions:

• The fluoroalkoxy molybdenum(V) reagent is a powerful and selective tool for oxidative coupling of aryls.
• Substitution of chlorido ligands with hexafluoroisopropoxido moieties enhances catalytic performance.
• The findings suggest potential applications for similar ligand modifications in other metal-based reagents.