Chemistry Letters, Vol.36, No.11, 1354-1355, 2007
A new class of acetophenone-based cinchona alkaloids as phase-transfer catalysts: Application to the enantioselective synthesis of alpha-amino acids
A new class of acetophenone-based cinchona alkaloid-derived quaternary ammonium salts were prepared and evaluated as phase-transfer catalysts in the enantioselective alkylation of glycine imine ester. +R3N-CH2COAr and electron-withdrawing 4'-NO2 moieties may play an important role leading to high enantioselectivity (85-> 99% ee).