The development of a Pd-catalyzed highly enantio-and diastereoselective [3+2] cycloaddition of 5-vinyloxazolidinones and activated trisubstituted alkenes is described in detail. This protocol for the single-step construction of densely functionalized pyrrolidines with three contiguous stereocenters including vicinal quaternary stereocenters depends on the remarkable ability of phosphine ligands possessing a chiral ammonium ion to promote intermolecular cycloaddition reactions with a precise control of absolute stereochemistry. A series of control experiments show that a chiral ammonium phosphine hybrid ligand enabled the individual, yet simultaneous stereocontrol of each chiral center in the annulation reaction. The reaction mechanism is also discussed with particular focus on the stereodetermining processes.

A catalytic transformation of N‐unprotected l‐amino esters to N‐protected d‐amino esters was developed. The combined use of a heteroaromatic aldehyde, Lewis acid, palladium complex, and chiral Brønsted acid was a key factor for the successful operation of this catalytic system. The synergistic cooperation of an appropriate aldehyde and Lewis acid was crucial for promoting an efficient racemization of l‐amino esters, while the combination of a palladium complex and chiral phosphoric acid enabled dynamic kinetic resolution through asymmetric N‐allylation, providing N‐protected d‐amino esters in good yields with up to 97 : 3 er. Following appropriate deprotection processes, d‐amino acids were obtained without loss of enantiomeric purity.

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The combination of 8-quinolinecarboxaldehyde and benzoic acid proved to be an effective catalyst system for the racemization of N-unprotected α-aryl-or α-alkyl-substituted α-amino amides. Application of this system to chemoenzymatic dynamic kinetic resolution provided an efficient access to enantiomerically pure N-acetyl-α-amino amides in good to high yields.Inspired by the enzyme cofactor pyridoxal-5′-phosphate (PLP), heteroaromatic or aromatic aldehydes

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