Asymmetric Enamide Hydrogenation Using Phosphinite Thioglycosides: Synthesis of d- and l-Aminoesters Using d-Sugars as Catalyst Precursors
摘要:
Diastereomerically pure cationic Rh(I) complexes derived from phosphinite thioglycosides I were used as catalysts in highly enantioselective hydrogenations of enamides. The conformational similarity of alpha-D-arabinopyranose with beta-L-galactopyranose allows the synthesis of both enantiomers of alpha-amino acid derivatives such as D- and L-DOPA in excellent ee (97% and 98%), using derivatives of the former sugar as catalyst precursors.