Enantioselective amination of alpha-phenyl-alpha-cyanoacetate catalyzed by chiral amines incorporating the alpha-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)2PYR and (DHQD)2PYR provided the product of amination with lower than 10% enantiomeric excess.
Liu
Yongjun
Y
Departamento de Química, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, 07000 México, D.F., Mexico.
Melgar-Fernández
Roberto
R
Juaristi
Eusebio
E