Chiral macrocycles host-guest inclusion complexes

A broad range of macrocyclic compounds can be used as chiral selectors for enantioselective HPLC. Besides synthetic crown ethers, derivatized cyclodextrins and cyclic antibiotics are also used as chiral stationary phases. Enantiomer separation employing these compounds is often based on host-guest interactions [15], whereby the cyclic molecules form an inclusion compound or an association complex with the analyte. 

An established area of application of macrocyclic polyethers is the stereoselective complexation of chiral guest primary alkylammonium salts by optically active host macrocycles. Full details of the resolution, optical stability, and inclusion into chiral hosts of the binaphthol (84), and also of the chiral recognition properties of crowns [e.g. (85)] based on simple carbohydrate precursors, have been reported this year. An extension of the latter work" utilizes derivatives of the more complex carbohydrates D-glucose and D-galactose. The macrobicyclic polyethers (86) derived from D-glycerol or pentaerythritol have been suggested as potential chiral (at the bridgeheads) cryptands. 

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