Inherent chirality through a simple dialkylation of 2,14-dithiacalix[4]arene

Abstract

The dialkylation of 2,14-dithiacalix[4]arene was studied employing various synthetic procedures known for the parent macrocycles (thiacalixarenes and/or classical calixarenes). The best results for distal dialkylation were achieved using the Mitsunobu reaction with the corresponding alcohols. Interestingly, due to the lower symmetry of the starting compound, the dialkylated derivatives represent inherently chiral systems. The introduction of chiral substituents thus leads to mixtures of diastereomers potentially useful for the separation of individual stereoisomers as demonstrated by chiral HPLC. The conformational behavior of the novel compounds was studied both in solution (NMR) and in the solid state (X-ray).