The First Catalytic Highly Enantioselective Alkylation of Ketimines—A Novel Approach to Optically Active Quaternaryα-Amino Acids
作者:Steen Saaby、Kimitaka Nakama、Mette Alstrup Lie、Rita G. Hazell、Karl Anker Jørgensen
DOI:10.1002/chem.200305302
日期:2003.12.15
anchoring was synthesized and allowed to react with various silylketene acetals in the presence of 5-10 mol % of a chiral Zn(OTf)(2)-(R,R)-Ph-pybox-aqua complex. The corresponding opticallyactive quaternary alpha-amino acid derivatives were obtained in high yields and with enantioselectivities ranging from 34 % up to 95 % ee. The catalyst was studied by (1)H NMR spectroscopy and X-ray crystallography