Oxygenation studies. Part 2. Rhodium(I)-catalysed autoxidation of oct-1-ene at ambient temperature and pressure

Abstract

Oct-1-ene and triphenylphosphine in benzene solutions are catalytically oxygenated to octan-2-one and triphenylphosphine oxide by dioxygen at ambient temperature and pressure in the presence of the complex [RhCl(PPh₃)₃](1). Minor quantities of heptanal and other products are also formed. The rate of the reaction is sensitive to the triphenylphosphine concentration and the ratio of the yields of the two principal products is sensitive to trace amounts of acid. An initial process giving 0.5 mol of octan-2-one per mol of catalyst precedes the catalytic reaction. Radical-chain processes have not been detected. The generation of a transient dioxetan at the metal centre is suggested to account for the formation of octan-2-one and heptanal.