Unstabilized Alkyl Radicals in Photochemistry: From Emerging Precursors to Reactivity

Carbon-centered radicals have progressively become indispensable tools in modern synthetic chemistry. Visible-light photochemistry has emerged as a powerful platform for organic transformations, enabling the selective generation of radical species under remarkably mild and sustainable conditions. The controlled generation of unstabilized alkyl radicals, however, remains one of the most challenging and rapidly evolving frontiers in the field. In recent years, substantial efforts have been devoted to the development of novel radical precursors specifically designed to enable the efficient formation of these highly valuable intermediates under photoinduced conditions. This Minireview highlights recent advances in the design of unstabilized carbon-centered radical precursors, systematically categorizing them according to their structural features. Particular attention is devoted to understanding how precursor design influences redox properties, bond fragmentation pathways, and so forth with the aim of laying the groundwork for the future design of increasingly efficient radical precursors and the discovery of new photochemical reactivity paradigms.