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 class of derivatives was studied, featuring a picolinamide unit bound to the alkaloid scaffold, further functionalized as quaternary ammonium salt at the quinuclidine ring. Excellent yields and from good to high enantioselectivities (up to 92% ee) were obtained in the reduction of ketoimines. The novel catalysts were successfully employed in the synthesis of an enantiomerically pure advanced precursor of the blockbuster drug Rivastigmine.
|Titolo:||Synthesis of an Advanced Precursor of Rivastigmine : Cinchona-derived Quaternary Ammonium Salts as Organocatalysts for Stereoselective Imine Reductions|
BENAGLIA, MAURIZIO (Corresponding)
|Parole Chiave:||Ketoimine reduction; Chiral amines; Cinchona alkaloid derivatives; Rivastigmine; Trichlorosilane|
|Settore Scientifico Disciplinare:||Settore CHIM/06 - Chimica Organica|
|Data di pubblicazione:||14-ott-2015|
|Digital Object Identifier (DOI):||10.1016/j.tetlet.2015.08.086|
|Appare nelle tipologie:||01 - Articolo su periodico|