Self-association free bifunctional thiourea organocatalysts: synthesis of chiral α-amino acids via dynamic kinetic resolution of racemic azlactones

Abstract

Concentration-independent high enantioselectivity in the dynamic kinetic resolution (DKR) of racemic azlactones affording chiral α-aminoesters has been achieved using self-association free thiourea-based dimeric cinchona alkaloid organocatalysts. Detailed experimental studies and single crystal X-ray analysis confirmed that these bifunctional organocatalysts I do not form H-bonded self-aggregates in either solution or solid state.