Russian Journal of General Chemistry. Vol. 92, No. 11, Pages 2390-2399, 2022

A. Uyanik^a^,*, O. Sahin^a, E. Akceylan^a, S. Eymur^b, I. Uyanik^c, and M. Yilmaz^a^,**

^aDepartment of Chemistry, Faculty of Science, Selçuk University, Konya, 42130 Turkey

^bDepartment of Energy Systems Engineering, Faculty of Engineering, Giresun University, Giresun, 28200 Turkey

^cDepartment of Metallurgical and Materials Engineering, Faculty of Technology, Selçuk University, Konya, 42130 Turkey

Abstract— A new organocatalyst trans-4-hydroxy-L-proline-derived calix[4]arene was synthesized and its catalyst performance for the direct asymmetric aldol reactions between cyclohexanone and different aromatic aldehydes was investigated. The effect of a series of reaction conditions such as solvent, water and additives were evaluated in detail, and it was observed that the addition of water had a big effect on the enantioselectivities. Specifically, high anti-diastereoselectivity (anti/syn = 92 : 8) and high enantioselectivity (ee 88%) were obtained from the reaction between cyclohexanone and 4-fluorobenzaldehyde in the presence of water.

Keywords: organocatalysis, direct asymmetric aldol reaction, L-proline, calix[4]arene

Effect of Calix[4]arene as a Hydrophobic Substituent on Proline Catalysis of Direct Asymmetric Aldol Reactions in the Presence of Water