Synthesis of an advanced precursor of Rivastigmine: Cinchona-derived quaternary ammonium salts as organocatalysts for stereoselective imine reductions
The enantioselective reduction of ketoimines has been successfully realized, using trichlorosilane as the stoichiometric reducing agent in the presence of catalytic amounts of a Lewis base, specifically a Cinchona derivative. For the first time, a novel c
Genoni, Andrea,Benaglia, Maurizio,Mattiolo, Emanuele,Rossi, Sergio,Raimondi, Laura,Barrulas, Pedro C.,Burke, Anthony J.
Cinchona alkaloid amides/dialkylzinc catalyzed enantioselective desymmetrization of aziridines with phosphites
The first highly enantioselective desymmetrization of aziridines with phosphites has been developed. Excellent yields and enantioselectivities were observed for the reaction with various aziridines using a new class of readily accessible chiral catalysts derived from 9-amino-9-deoxy-epi-cinchona alkaloids. In studies probing the reaction mechanism, we observed some complexes for the cinchona alkaloid amide-Zn(II) by ESI-MS analysis.