In pyridine, bis(2,2′-bipyridine)iron(II) (Fe(bpy)2+ 2) activates hydrogen peroxide for the efficient and selective catalytic dehydrogenation (oxidation) of veratryl alcohol (model-substrate monomer for lignin; 3,4-(MeO)2PhCH2OH). Several other complexes (FeII(OPPh3)2+ 4, FeII(O2bpy)2+ 2, FeII(MeCN)2+ 4, FeII(PA)2, FeIIICl3) are effective catalysts for the dehydrogenation of veratryl alcohol and benzyl alcohol, but their selectivity (relative reactivity with 3,4-(MeO)2PhCH2OH vs. PhCH2OH) is less than the 6.1 ratio that is observed for the optimized FeII(bpy)2+ 2/H2O2/pyridine(py) system. The reactivities have been determined for several other methoxybenzyl alcohols that are model substrates for lignin (e.g.,4-MeOPhCH2OH and (MeO)3PhCH2OH).
