A 5 mol% IMesCuCl (13.6 mg) catalyst was added to an anhydrous toluene (1 mL) solution of 1,1-disubstituted epoxide (0.2 mmol). The resulting reaction mixture was heated under reflux for several hours. DAM (0.3 mmol) was slowly added dropwise to the reaction system using a syringe pump over approximately 2 hours. The reaction vessel was then sealed, and the reaction was stirred under reflux for another 2 hours. After the reaction was complete, a saturated NH4Cl aqueous solution (1 mL) was added to the reaction mixture to quench the reaction. The reaction mixture was extracted twice with dichloromethane (3 × 2 mL). The organic layers were then combined, the organic components were washed with brine, and the organic layers were dried with anhydrous Na2SO4. The combined organic matter was filtered to remove the drying agent. The filtrate was concentrated under reduced pressure. The residue was purified by silica gel (n-hexane/ethyl acetate = 10:1~3:1) column chromatography to obtain the target product, juniperene.
Figure: Synthetic Route of SABINENE
