Recent advances in the photocatalytic Giese reaction

The Giese reaction is a key method for forming C–C bonds via the radical addition to electron-deficient alkenes. Recent advances have shifted this transformation towards photocatalytic approaches that use visible light to generate carbon-centered radicals under mild and sustainable conditions. This review highlights developments from 2020 to 2025 in photocatalytic radical generation using metal-based complexes (especially ruthenium and iridium) and organic photocatalysts. Emphasis is placed on how light-driven processes enable efficient, selective, and environmentally friendly Giese-type reactions with diverse substrates. These innovations demonstrate the growing importance of photochemistry in modern radical synthesis.