1995 Volume 53 Issue 7 Pages 633-644
Heteroaromatic N-oxides were found to be excellent oxidants in the presence of ruthenium porphyrin. 2, 6-Disubstituted pyridine N-oxides plus a catalytic amount of Ru porphyrin oxidized olefins, sulfides, and ally or benzyl alcohols to afford epoxides, sulfoxides, and aldehydes, respectively, in high yields. These oxidations also proceeded using various heteroaromatic N-oxides, such as pyrazine N-oxides, as oxidants. Further, the oxidizing activity of this reaction system was greatly enhanced by the addition of acids such as hydrogen chloride or hydrogen bromide. The system in the presence of these acids effectively oxidized unactivated alkanes and aromatic compounds to give alcohols (or ketones) and p-quinones in high yields with high selectivity and an extremely high catalyst turnover number (up to 120, 000). This system offers practical advantages, such as mild conditions, tractability of oxidants and easy overall procedures.
