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.