AEROBIC EPOXIDATION VIA ALKYL-2-OXOCYCLOPENTANECARBOXYLATE COOXIDATION WITH COBALT OR MANGANESE JACOBSEN-TYPE CATALYSTS

In the presence of methyl, tert-butyl, or (-)-menthyl esters of 2-oxoc yclopentanecarboxylic acids Jacbosen-type complexes of cobalt(II) and manganese(III) form active catalysts for alkene epoxidation using mole cular oxygen. Alkyl-1-hydroxy-2-oxocyclopentanecarboxylates and 1-alky l-2-oxo-hexanedicarboxylic acids are formed as co-oxidation products. The (-)-menthyl/cobalt system is selective for epoxide production but the products are racemic consistent with radical epoxidation in soluti on rather than at the cobalt complex. The manganese Jacobsen-type comp lex gives lower yields of epoxides (40-60%) but for 2,2-dimethylchrome ne and styrene these are optically active (12-60% ee).