A stereoselective approach for the total synthesis of [2(S)-phenyl-propionyl]-2-piperidinone-3-(R)-yl-ester and its diastereomer

Stereoselective total synthesis of isomers of [2-phenyl-propionyl]-2-piperidinone-3(R)-yl-ester has been achieved using commercially available starting materials like trans cinnamaldehyde and 4-pentene-1-ol. The key steps are Steglich conditions for the esterification of the two crucial intermediates; reduction of the azide to amine under Staudinger reaction conditions with concomitant intramolecular amidation reaction in one pot afforded the target compound(s). However, the total syntheses revealed that the structural revision is necessary for the reported natural product.