Producing aryl halides from lignin.

Lignin represents the most abundant biomass resource, which contains aromatic units. Lignin refinery is a promising, sustainable alternative for the production of aromatic chemicals. However, depolymerization and transformation of lignin into aryl halides, which are indispensable chemicals in both the academic and industrial communities, remain challenging. Here, we report a simple and mild method for the depolymerization and halogenation of lignin, leading to the production of useful aryl halides. Notably, hydrogen bond activation for halogenation reagents is essential for substantially increasing the reactivity, resulting a highly efficient cleavage of C-C bonds in lignin. This method is highly selective for breaking C(sp)-C(sp) bonds of lignin linkages, enabling the application of precise depolymerization and halogenation reactions from lignin models to native lignin from various wood resources, which provides a sustainable and efficient access to various synthetically useful aryl halides.