Application of the Bichromophoric Exciton Chirality Method to the Stereochemical Elucidation of Acyclic Polyols

The recently developed technique of bichromophoric derivatization extends the utility of the exciton chirality method. Selective introduction of two types of exciton chromophores to two different types of hydroxyl groups gives rise to highly characteristic CD curves. Pairs of chromophores are evaluated for two different applications: 1) an oligosaccharide linkage analysis, and 2) elucidation of stereochemistry in acyclic polyhydroxyl compounds with two or more stereocenters. For the latter application, selective introduction of the 9-anthroate chromophore (lemax = 253 nm) at prirnary hydroxyls, together with the p-methoxycinnamate chromophore (,1,m" = 311 nm) introduced at secondary hydroxyls of stereocenters, gives rise to highly characteristic CD spectra. Examination by this method of all diastereomeric n-tetrose and n-peritose diethyl dithioacetals indicates that the anthroate/methoxycinnamate bichromophoric approach is a promising method for assignment of stereochemistry in 1,2,3-triols, 1,2.3,4-tetrols,and other polyhydroxylated compounds