Stereochemistry and recognition properties of calixarenes

Abstract

The conformational changes among several conformational isomers of calix [4] arenes can take place because the OH groups rotate through the annulus. This inversion was inhibited by the introduction of the substituents bulkier than ethyl group into the OH groups and the resulting conformational isomers were separated. The selective syntheses of all partially O-propylated compounds and conformational isomers in p-tert-butylcalix [4] arene were successful by the combination of protection-deprotection method and the optimization of the reaction conditions (base, temperature, solvent, etc). Several of these compounds can possess the chirality which is caused by the disappearance of the symmetries on the conformation or based on the order in the array of different substituents. We succeeded in the syntheses and the optical resolutions of these calixarenes with molecular chirality for the first time. © 1995, The Society of Synthetic Organic Chemistry, Japan. All rights reserved.