Anodic cleavage of lignin model dimers in methanol

Article abstract of DOI:10.1016/S0040-4020(01)88262-4

The anodic oxidation in methanol of some lignin model compounds, the C₁₇-C₁₈ compounds ((1) - (5), has been studied to ascertain factors influencing cleavage of C_α - C_β bonds cf. substitution. Cyclic voltammetric oxidation peak potentials were influenced by structure but not by pH. Preparative-scale electrolyses gave 3,4-dimethoxybenzaldehyde as the major product from compounds (1) - (3), corresponding to cleavage of th C_α - C_β bonds. In contrast compounds (4) and (5) were not cleaved with significant efficiency. The results are convincingly rationalised in terms of rapid cleavage of the C_α - C_β bonds in the first-formed radical cations.