Enantioselective amination of α-phenyl-α-cyanoacetate catalyzed by chiral amines incorporating the α-phenylethyl auxiliary

Nineteen chiral amines and their derivatives were prepared and investigated as organocatalytic Lewis bases in the alpha-amination of ethyl alpha-phenyl-alpha-cyanoacetate. For comparison purposes, a few natural products were also examined as catalysts in this study. Among the results obtained, (R)-N-benzyl-N-(1-phenylethyl)-amine and (R,R)-N,N'-bis(1-phenylethyl)-propane-1,3-diamine as the catalysts afforded the amination products in excellent yields and with up to 84% ee. By contrast, under comparable conditions the two derivatives of natural products (DHQ)(2)PYR and (DHQD)(2)PYR provided the product of amination with lower than 10% enantiomeric excess.