Asymmetric Synthesis of the Four Stereoisomers of 4-Hydroxypipecolic Acid
作者:Franklin A. Davis、Tianan Fang、Bin Chao、David M. Burns
DOI:10.1055/s-2000-8710
日期:——
The asymmetric synthesis of all four stereoisomers of 4-hydroxypipecolic acid (1) from the polyfunctionalized chiral building blocks δ-amino β-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 δ-amino β-keto esters 5 to cis-4-hydroxy 2-piperidinone 7 and syn-δ-amino β-hydroxy ester 9, respectively. The only protecting/deprotecting group chemistry required is related to the oxidation step.