H2O2/NaHCO3-mediated enantioselective epoxidation of olefins in NTf2-based ionic liquids and under ultrasound

The bicarbonate-activated peroxide (BAP) system has been shown to constitute an excellent and versatile combination for the epoxidation of olefins. Herein, we demonstrate that the benign H2O2/NaHCO3 oxidative combination can be used for the enantioselective epoxidation of olefins using a chiral manganese porphyrin as a catalyst. This unprecedented result was made possible by the use of an ionic liquid with ultrasound, which leads to the activation of Mn-porphyrin catalysis.

This first example of ultrasonic asymmetric catalysis in ionic liquids clearly proves that the mechanism involves the porphyrin catalyst rather than the classical bicarbonate-activated peroxide (BAP).Figure optionsDownload high-quality image (145 K)Download as PowerPoint slideHighlights
► Optimization of ionic liquids syntheses in terms of green chemistry.
► Environmentally benign H2O2/NaHCO3 combination used for enantioselective epoxidation of olefins.
► Ultrasound/ionic liquids combination prevents the bleaching of Mn catalyst.
► Mechanism for olefins epoxidation catalyzed by Mn-porphyrin in ionic liquid under ultrasound.