Depolymerization strategies for lignin valorization toward valuable aromatic compounds

Lignin, the second largest biomass next to cellulose, is potentially the richest renewable resources of aromatic compounds in nature. Although controlled depolymerization of lignin is an intense focus of research, its complex and diversely linked structure hampers the development of a reliable process for the production of fine aromatic chemicals. Arguably, disconnection of β-O-4 linkages by C-O bond cleavage is the key reaction to produce low-molecular-weight valuable aromatics from lignin. This short review describes recent advances of C-O bond cleavage reactions in dimeric lignin model compounds, as well as isolated natural lignin polymers. © 2020 Society of Synthetic Organic Chemistry. All rights reserved.