A meso specific reaction

Abstract Acid-catalyzed condensation of optically pure 5-(hydroxymethyl)-2-pyrrolidmone, 2 , with benzaldehyde gives only a monomeric optically active oxazoliduie, 3 , while under the same conditions, racemic 2 gives only a meso centrosymmetric compound 4 - a dimer of racemic 3 . This meso specific reaction serves as a highly efficient method for increasing the optical purity of the generally useful chiral building blocks 2 and 3 .