Cleavage/cross-coupling strategy for lignin valorization

<p indent="0mm">Lignin is the most abundant renewable aromatic resource in nature. The degradation of lignin into small organic molecules to replace fossil-derived compounds is crucial for sustainable resource development. Current strategies primarily focus on directly cleaving C−O/C−C bonds in lignin to obtain oxygen-containing compounds and hydrocarbons; however, these methods typically produce relatively simple products. Future lignin biorefineries will require a diverse range of fine chemicals to enrich the variety of lignin degradation products and enhance their added value. In this context, the cleavage/cross-coupling strategy provides a novel approach for converting lignin into high-value chemicals. This review summarizes recent advances in the application of cleavage/coupling strategies for the degradation of lignin and its model compounds. This strategy cleaves lignin linkages while coupling with other compounds (<italic>e</italic>.<italic>g</italic>., nitrogen-containing, oxygen-containing, sulfur-containing compounds), generating a wide variety of high-value chemicals, such as amines, amides, arylamines, nitriles, nitrogen-containing heterocycles, esters, ethers, thioethers, and silicon-containing compounds. Additionally, the degradation of lignin and its model compounds into different types of fine chemicals is briefly summarized. Finally, the challenges faced in current lignin cleavage/cross-coupling reactions for future development are discussed.