The effect of pH control on the selective ruthenium-catalyzed oxidation of ethers and alcohols with sodium hypochlorite

Highly selective oxidations of ethers to esters or lactones and of secondary alcohols to ketones were achieved using catalytic amounts ofvarious Ru precursors and the theoretical amount of NaOCl. Reactions were carried out in biphasic solvent mixtures at constant pH 9 ± 9.5 via either feed-on-demand addition of HCl and NaOH or in the presence of NaHCO3/Na2CO3 buffer. The catalyst could be easily recycled for at least 4 times with only minor loss in selectivity. Products were generally recovered by simple phase separation and evaporation of the organic solvent. The effects of catalyst precursor, additives and pH control method are also described.