Selective epoxidation of terminal alkenes catalyzed by cobalt complexes

Abstract

The selective epoxidation of terminal alkenes catalyzed by cobalt(II) complexes in the presence of 2-ethylbutyraldehyde/oxygen as oxidant was examined under mild conditions. Cobalt calix[4]pyrrole or benzimidazole with no previous report as a catalyst for terminal alkene epoxidation have been disclosed to be effective catalysts. Under the developed conditions, 1-dodecene as a chemical model was transformed into 1-dodecene oxide as a sole product with high yield and excellent selectivity. Applications of this developed epoxidation epoxidation could be accomplished with various terminal alkenes and gave the desired products in moderate to high yield. Regioselectivity study performed using 4-vinylcyclohexene implied that terminal double bond was less reactive than endocyclic double bond.