Complex Prolyl Peptides in Two Steps: Biocatalysis and Ugi Reaction

Significance

Orru, Turner, and colleagues report an expedient enantioselective synthesis of prolyl peptides 3 by a monoamine oxidase catalyzed desymmetrization of 1 followed by a three-component Ugi reaction. The initial biotransformation that yields enantioenriched imines 2 was found to undergo a highly 2,3-trans-diastereoselective Ugi reaction with the stereochemical outcome directed solely by the configuration of the chiral imine 2 and not the other components. Starting from bicyclic imines 4, the authors also obtained a range of enantiopure prolyl peptide derivatives 5.