Epoxidation of olefins with homogeneous catalysts-quo vadis?

The epoxidation of olefins catalyzed by molecular transition metal compounds is a research field, which has been extensively studied over the past forty years. To date, numerous types of complexes have been presented as widely applicable and highly efficient. This Perspective Article gives a summary of the most active catalysts for the epoxidation of some most frequently applied olefins, such as cyclooctene, 1-octene, prochiral olefins and industrially relevant olefins.