[5]HELOL phosphite: A helically grooved sensor of remote chirality

Even when the first center of chirality is far from a functional group, the stereochemistries of chiral molecules can be sensed if the functional grou p is attached to a phosphorus embedded within the groove of a nonracemic he licene. The sensor used was a phosphite ester of [5]HELOL, structure 6, and P-31 NMR spectroscopy was the method of analysis. Although there are seven methylene between the hydroxyl and the first center of chirality, the P-31 NMRs could distinguish the enantiomers of 8-phenylnonanol with baseline re solution. However, to achieve this resolution, the solvent has to be chosen appropriately. The probe can also analyze the enantiomers of other alcohol s, amines, phenols, and, when they were coupled to 2-aminophenol, carboxyli c acids. The sensitivity to remote chiral centers of the moieties analyzed is attributed to their confinement to the helical groove.