Exploration of the Chiral Recognition of Sugar-Based Diindolylmethane Receptors: Anion and Receptor Structures.

In this study, we have conducted a systematic investigation of the chiral recognition of carboxylic anions by D-glucuronic acid/diindolylmethane receptors. We investigate the influence of the anion structure on chiral recognition in the diindolylmethane/glucuronic acid-based receptor 1 a. We found that presence of an additional hydrogen-bond donor at the α position to the carboxylic function is essential for effective chiral differentiation in these systems. Furthermore, we present a synthetic procedure that allows for the synthesis of sugar-decorated receptors that possess a modified substituent at the anomeric position. Four new receptors 1 b-e have been synthesized, and their chiral-discrimination ability toward model carboxylates is studied. The obtained results show that the chiral recognition of these receptors can be fine-tuned by incorporation of a proper substituent into the receptor structure.