Abstract

Photoredox catalysis is a powerful tool in organic synthesis utilized to generate carbon radical intermediates. With the implementation of a triphenylphosphonium salt as a radical precursor, carbon radicals can be produced in a novel approach from the homolytic cleavage of the carbon-phosphorus bond. Additionally, photoredox catalysis uses the sustainability of visible light, rather than UV light or heat, in organic synthesis. Preliminary experiments showed that benzyltriphenylphosphonium bromide primarily underwent a dimerization reaction under photoredox catalysis conditions. Once the optimized conditions were obtained, the substrate scope was explored to investigate the reactivity of arenes with varying electron-withdrawing and electron-donating functional groups. The substrate scope study revealed that substrates with electron-donating group substituents primarily undergo dimerization, and substrates with electron-withdrawing group substituents undergo reduction. Mechanisms for the dimerization and reduction reactions are proposed.