Stereoselective Synthesis of Hydroxypipecolic Acids

Significance

Reported is the stereoselective synthesis of cis-4 and trans-3 pipecolic acids from 2,3-epoxy-5-hexen-1-ol. This epoxide is easily available through Sharpless asymmetric epoxidation of the parent alkene. The route leads to the specific pipecolic acids shown; the preparation of analogues was not investigated. The synthetic route is well designed and relatively short, with good yields at each step.