‘Tailor-made’ Polymers for the Removal of Lamellar Twinning: Resolution of α-Amino Acids by Entrainment

Pure enantiomers are frequently prepared by the technique of resolution by entrainment. However, this does not work if the samples are lamellarly twinned conglomerate crystals, which is often the case for α-amino acid salts, especially amphiphilic ones. A method based on the addition of chiral /6tailor-made′ enantioselective crystal nucleation inhibitors is presented that prevents lamellar twinning and allows resolution of hydrophobic racemic α-amino acids by kinetic crystallization. The role of the /6tailor-made′ additive is shown to provide evidence for the presence of structured clusters in supersaturated solutions.