Selected Free Radical Reactions

Many useful bond‐forming reactions and functional group manipulations involve free radicals. This chapter discusses selected free radical reactions. It covers radical reactions initiated by chemical means, photoredox catalysts and electrochemical methods. Photoredox catalysis emerged as a powerful tool to induce or accelerate chemical transformations via single‐electron transfer events. The introduction of iridium‐ and ruthenium‐based photoredox catalysts has opened up new pathways into radical formation from visible light. Electrochemistry provides another synthetic tool for performing single‐electron transfer redox chemistry, allowing for selective oxidation or reduction or organic functional groups or metals via direct electron transfer at an electrode. Such reactions can generate radical, radical cation, or radical anion intermediates or turn over catalysts without using chemical redox reagents, giving rise to reaction conditions that are potentially milder and less environmentally harmful.