Catalytic aerobic oxidation of diols under photo-irradiation: highly efficient synthesis of lactols

Aerobic oxidation of 1,n- and 1,ω-diols with (ON)Ru(salen) 1 as the catalyst was found to give the corresponding lactols in almost quantitative yields. Furthermore, in the oxidation of 2,2-dimethylalkane-1,ω-diols, less sterically hindered ω-alcohols were found to be preferentially oxidized when (ON)Ru(salen) 6 was used as the catalyst. n-Decanol was preferentially oxidized in the presence of 2,2-dimethylpropanol also by using 6 as the catalyst.