Radical Addition to Carbonyls (or C = X) Enabled by Visible Light Photoredox or Not

This chapter highlights the recent advances in radical addition reaction to carbonyls and the derivatives, as an attractive alternative to polar addition reactions for organic synthesis, focusing on literature published after 2014. Radical addition reactions offer milder conditions, enhanced selectivity, and broader functional group compatibility. These advancements open new possibilities for efficient synthesis of complex molecules in pharmaceuticals and materials science. This chapter focuses on recent progress in introducing radicals to C = X (X = O or N) bonds, with a particular emphasis on photocatalytic radical reactions driven by visible light and stereoselective radical reactions.