Parallel kinetic resolution of active esters using designer oxazolidin-2-ones derived from phenylglycine

The parallel kinetic resolution of racemic pentafluorophenyl 2-phenylpropionate using an equimolar combination of quasi-enantiomeric oxazolidin-2-ones is discussed. The levels of diastereoselectivity were excellent (>90% de) leading to separable quasi-enantiomeric oxazolidin-2-one adducts in good yield. This methodology was subsequently used to resolve a series of 2-aryl propionic and butanoic acids.