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1: J Org Chem. 2007 Sep 28;72(20):7688-92. Epub 2007 Sep 6.Click here to read Links

Enantioselective synthesis of trans-4-methylpipecolic acid.

Alegret C, Santacana F, Riera A.

Unitat de Recerca en Síntesi Asimètrica (URSA-PCB), Institute for Biomedical Research and Departament de Química Orgànica, Universitat de Barcelona, Parc Científic de Barcelona c/Josep Samitier, 1-5, 08028 Barcelona, Spain.

An asymmetric synthesis for the preparation of both enantiomers of trans-methylpipecolic acids is described. It is based on Sharpless epoxidation as a chirality source, regioselective ring opening with allylamine, and ring-closing metathesis to construct the piperidine ring. The stereogenic center at C-4 is set by stereoselective hydrogenation that is directed by the alcohol functionality of an intermediate and proceeds with good diastereomeric control (trans/cis 16/1). Crystallization of the Boc-protected amino acid afforded the target products with excellent chemical (98% de) and enantiomeric purity (99% ee).

PMID: 17803317 [PubMed - indexed for MEDLINE]