Efficient access to N-protected derivatives of (R,R,R)- and (S,S,S)-octahydroindole-2-carboxylic acid by HPLC resolution

The preparation of the proline analogue (2S,3aS,7aS)-octahydroindole-2-carboxylic acid (Oic) and its enantiomer, (2R,3aR,7aR)-Oic, is described. A racemic precursor has been synthesized in good yield and subjected to HPLC resolution on a chiral column. The high efficiency of both the synthetic and chromatographic procedures has allowed the isolation of multigram quantities of each amino acid in enantiomerically pure form and suitably protected for use in peptide synthesis.Financial support from the Ministerio de Educación y Ciencia–FEDER (Project CTQ2004-5358) and Gobierno de Aragón (Project PIP206/2005 and research group E40) is gratefully acknowledged. The authors thank Ana Lidia Bernad for technical assistance with HPLC. This project has been funded in whole or in part with Federal funds from the National Cancer Institute, National Institutes of Health, under contract number NO1-CO-12400. The content of this publication does not necessarily reflect the view of the policies of the Department of Health and Human Services, nor does mention of trade names, commercial products, or organization imply endorsement by the US Government. This research was supported (in part) by the Intramural Research Program of the NIH, National Cancer Institute, Center for Cancer Research.Peer reviewe