The asymmetric synthesis of all four stereoisomers of 4-hydroxypipecolic acid (1) from the polyfunctionalized chiral building blocks d-amino b-keto esters (S S ,R)-(+)-5 or (R S ,S)-(-)-5 is described. Key steps in the synthesis are the stereoselective reductions of b-phenylpiperidine-2,4-dione (6) and N-sulfinyl d-amino b-keto esters 5 to cis 4-hydroxy 2-piperidinone 7 and syn-d-amino b-hydroxy ester 9, respectively. The only protecting/deprotecting group chemistry required is related to the oxidation step.