Epoxides ring opening reaction utilizing transition metal catalysts

Abstract

The comparative study on the epoxide ring opening catalyzed by three groups of catalyst: transition metal salt, metal Schiff's base and metal carboxylate complexes were thoroughly explored. For some metal salts such as anhydrous FeCI₃, the epoxide ring opening could efficiently be occurred in good yield. Among metal Schiff s base complexes, especially Cr(salen)CI could be employed as a potent catalyst for this purpose and gave the desired product in high yield. For metal carboxylate complexes, Fe(benzoate)₃, Fe(4-nitrobenzoate)₃, Fe(2,4-dinitrobenzoate)₃, Fe(picolinate)₃ and Fe(TCA) ₃•1.5H₂0 had never been utilized as a catalyst in epoxide ring opening reaction. Fe(TCA) ₃•1.5H₂0 exhibited the most effective catalyst for styrene oxide ring opening reaction gave 2-methoxy-2-phenylethanol in almost 100% yield at ambient condition for 10 min. A series of experiments to optimize the reaction conditions including type of nucleophile, solvent system, temperature and reaction time was cautiously conducted. The optimum conditions were further applied for other five epoxides namely, 1-dodecene oxide, cyclohexene oxide, butyl glycidyl ether, tert-butyl glycidyl ether and α-pinene oxide, which could produce the corresponding epoxide ring opening product in moderate to high yield.