Accelerating radicals generation by photoredox catalysis from organoborates in continuous microflow reactor

During the last decade continuous microflow processes have received an increasing amount of attention to facilitate photoredox catalyzed reactions. Indeed, under continuous flow conditions, more sustainable, safer and easier scalable processes could be developed with respect to conventional batch procedures. In such reactors, improved irradiation of the reaction medium impacts the photoredox catalyzed process. The generation of carbon-centered radicals via oxidation of alkyl-, allyl-, and benzylborates by photoredox catalysis under UV irradiation was significantly faster in continuous flow microreactors. The generated radicals smoothly react with TEMPO and electron-deficient alkenes to afford coupling products.