Catalytic asymmetric epoxidation of limonene using manganese Schiff-base complexes immobilized in ionic liquids

The asymmetric epoxidation of limonene has been performed using Jacobsen’s catalyst dissolved in 1-n-butyl-3-methylimidazolium tetrafluoroborate (BMI · BF4) ionic liquid and with hydrogen peroxide oxidant giving high stereoselectivity. Limonene was selectively converted into 1,2-epoxi-p-ment-8-enes with a diastereoisomeric excess of 74% and conversions up to 70%. Chirality of limonene was found to play an important role in stereochemical formation of new chiral centers because the synthesis occurs with double asymmetric induction.Figure optionsDownload full-size imageDownload as PowerPoint slide