Copper-Catalyzed Oxidative Cleavage of the C–C Bonds of β-Alkoxy Alcohols and β-1 Compounds

Abstract

Copper-catalyzed aerobic oxidation conditions were employed to promote the C−C bond cleavage of β-alkoxy alcohols and β-1 compounds (lignin model compounds). Besides these compounds, various 1,2 and 1,3-diols were successfully converted to aldehydes. We propose the Cu(I)-catalyzed mechanism explaining the C−C cleavage of these 1,2 and 1,3-dihydroxy compounds and β-alkoxy alcohols based on XPS data. Although our reaction conditions do not include large excess of bases and elaborated ligand-modified catalysts, copper salts with/without Me-TBD show good catalytic activities for C−C bond cleavage of various lignin model compounds.

Perspective on oligomeric products from lignin depolymerization: their generation, identification, and further valorization

“…For instance, Kim et al had effectively activated the C–C bond cleavage in β-alkoxyl and β-1 lignin model dimers via copper-catalyzed oxidation although the same strategy had been tested with raw lignin. 151 Ren et al tested a similar approach for alkaline lignin at room temperature, and the 2D-HSQC-NMR results suggested a selective cleavage of the aliphatic C–C bond from the lignin although the dimeric-trimeric aromatic acids and aldehydes were identified as the main products. 133…”