Synthesis of C2 Symmetric Organocatalysts and Investigation of Their Asymmetric Induction Effects in Aldol Reactions

Studies concerning optically active compounds occopy very important places both in industry and academic fields. Asymmetric catalysis is considered as an ideal method for synthesizing optically active compounds. Asymmetric induction in stereochemistry is described as the preferential formation of one enantiomer or diastereoisomer over the other in a chemical reaction as a result of the influence of a chiral feature present in the substrate, reagent, catalyst or environment, which is a key element in asymmetric synthesis, first introduced by Emil Fischer based on his work on carbohydrates. The field received three Nobel Chemistry prizes for its importance. In this study, two L-proline–based organocatalysts were prepared through modified literature procedures. These compounds were identified by 1 H and 13C NMR and IR spectroscopy. Subsequently, their asymmetric induction in the aldol reaction between cyclohexanone and substituted benzaldehydes was evaluated. Both catalysts efficiently promoted the reactions, providing the respective aldol products with enantiomeric excesses of up to 94%.