Hydrogen-peroxide epoxidation of natural olefins catalyzed by a dinuclear manganese complex

摘要

The complex of Mn(IV) with the macrocyclic N-containing ligand 1, 4, 7-trimethyl-1, 4, 7-triazacyclononane (L) [L_2Mn_2O_3](PF_6) catalyzes epoxidation of (+)-limonene in CH_3CN solution at room temperature. Adding CH_3COOH accelerates the reaction. The products are isomers of limonene epoxide with predominance of that with an epoxified ring double bond. Epoxidation of α-and β-pinene by this system is less effective, apparently due to extensive steric shielding of the double bonds in the pinenes.