This work was made possible by a grant from The Danish National Research Foundation. We are grateful to Dr. R. G. Hazell for X-ray crystallographic analysis.
Direct Organocatalytic Enantioselective Mannich Reactions of Ketimines: An Approach to Optically Active Quaternary α-Amino Acid Derivatives†
Article first published online: 25 AUG 2004
Copyright © 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
Angewandte Chemie International Edition
Volume 43, Issue 34, pages 4476–4478, August 27, 2004
How to Cite
Zhuang, W., Saaby, S. and Jørgensen, K. A. (2004), Direct Organocatalytic Enantioselective Mannich Reactions of Ketimines: An Approach to Optically Active Quaternary α-Amino Acid Derivatives. Angew. Chem. Int. Ed., 43: 4476–4478. doi: 10.1002/anie.200460158
- Issue published online: 25 AUG 2004
- Article first published online: 25 AUG 2004
- Manuscript Received: 30 MAR 2004
- amino acids;
- chiral amines;
- Mannich bases;
- quaternary stereocenters
You're in control of which diastereomer of a quaternary α-amino acid derivative is formed in a direct organocatalytic diastereoselective and enantioselective Mannich reaction of ketimines with aldehydes (see scheme). The reactions are high yielding and can be controlled through the choice of the catalyst to give either diastereomer of the product with diastereomeric ratios as high as >20:1 and with 83–98 % ee. Pg=protecting group.