Degradation of 1-(3,4-dimethoxyphenyl)-2-(2-methoxyphenoxy)propane-1,3-diol (1), a model compound for lignin beta-O-4 linkage was examined with iron, ruthenium, rhodium and iridium complexes bearing cyclopentadienone ligand. Cyclopentadienone iron complex gave only a small amount of degraded product with reduced molecular weight. Cyclopentadienone ruthenium complex, so called Shvo's catalyst, afforded 3,4-dimethoxybenzaldehyde (a3) in 14.3% yield after C alpha-C beta bond cleavage. On the other hand, cyclopentadienone group-9 metal complexes catalyzed C beta-O bond cleavage to afford guaiacol (b1) as a main product in up to 74.9% yield.