BISGUANIDINIUM CATALYZED ENANTIOSELECTIVE PHASE-TRANSFER DESYMMETRIZATIONS

Abstract

NOVEL TYPES OF CHIRAL PHASE TRANSFER CATALYSTS PENTANIDIUM SALTS, BIGUANIDINIUM SALTS AND TRISGUANIDINIUM SALTS WERE DESIGNED, SYNTHESIZED AND CHARACTERIZED. THE SYNTHETIC PROCEDURE WAS ALSO OPTIMIZED TO BE MORE SIMPLIFIED AND ENABLE MORE MODIFICATION ON THE CATALYSTS? STRUCTURES, AND GRAM-SCALE SYNTHESIS OF THE CATALYSTS WAS ALSO REALIZED. BY EMPLOYING THOSE CHIRAL PHASE-TRANSFER CATALYSTS, WE STUDIED THE DESYMMETRIZATION OF DIBROMOKETONES WITH VARIOUS ALIPHATIC AND AROMATIC ACETATES. WITH THE OPTIMIZED CONDITION, EXCELLENT YIELDS (UP TO 96%) AND EE VALUES (UP TO 90%) COULD BE ACHIEVED. FURTHER TRANSFORMATION OF THE PRODUCTS TOWARDS MULTICYCLIC STRUCTURES WAS EXPLORED. THE REACTION MECHANISM WAS ALSO STUDIED BASED ON EXPERIMENTAL RESULTS.