A comparative study of the asymmetric epoxidation of aromatic olefins using the first generation manganese salen epoxidation catalysts and their light fluorous variants: an interesting discovery on the use of benzotrifluoride as a cosolvent

The asymmetric epoxidation of aromatic olefins using optically active first generation manganese salen catalysts and light fluorous variants was examined. Although a slight decrease in the enantioselectivity of the product was observed when light fluorous catalysts were employed, the activities of these catalysts were higher than those of the non-fluorous catalysts. Additionally the influence on enantioselectivity of the oxidation was examined when fluorous cosolvents were used. The enantioselectivity of the oxidation increased with the addition of benzotrifluoride (BTF) regardless of whether a fluorous or non-fluorous salen catalyst was used. (C) 2014 Elsevier Ltd. All rights reserved.