Preassembly-Controlled Radical Recombination at Bismuth: Decarboxylative C─N Coupling with Sulfonamides

Area of Science:

• Organic Chemistry
• Catalysis
• Photoredox Catalysis

Background:

• Persistent transition metal radicals are key in metallaphotoredox catalysis for radical trapping and coupling.
• Bismuth radical chemistry offers potential but requires strategies for controlled reactivity.
• Selective radical reactions are expanding beyond d-block elements.

Purpose of the Study:

• To develop a novel strategy for controlling bismuth radical intermediates in organic synthesis.
• To enable selective C-N bond formation using bismuth-based radical chemistry.
• To explore preassembly as a method to direct radical recombination pathways.

Main Methods:

• Utilizing a preassembly strategy to enforce selective recombination between bismuth(II) and organic radicals.
• Investigating inner-sphere reaction pathways for radical coupling.
• Applying metallaphotoredox principles to bismuth chemistry.

Main Results:

• Demonstrated successful C-N coupling product formation via a bismuth-mediated pathway.
• Showcased the efficacy of preassembly in controlling radical-radical recombination.
• Established an inner-sphere mechanism for the observed coupling reaction.

Conclusions:

• Preassembly is a powerful strategy for controlling bismuth radical reactivity.
• This work expands the scope of metallaphotoredox catalysis to include bismuth.
• The developed method provides a new route for selective C-N bond formation.