Oxygenation studies. Part 9. Mechanistic studies on the oxygenation of cyclooctene at [{RhCl(C8H14)2}2]
Abstract
The complex [{RhCl(C8H14)2}2] in benzene containing cis-[5-2H1]-cyclooctene has been shown to undergo ligand exchange at 26°C at a very much faster rate than oxygenative breakdown. Double-bond isomerisation competes with the latter. The principal oxygenated product is a mixture of monodeuterioisotopomers of cyclooctanone which has been shown, by 13C NMR analysis, to have been formed by oxygenative attack on the vinylic carbons rather than on the allylic centres or on π-allylic intermediates. The findings are related to earlier mechanistic proposals for oxygenation of alkenes catalysed by rhodium species.