A GENERAL, MULTITECHNIQUE APPROACH TO THE STEREOCHEMICAL CHARACTERIZATION OF 1,2-DIARYLETHANE-1,2-DIOLS

摘要

A general method which allows the nonempirical stereochemical characterization of 1,2-diarylethane-1,2-diols, obtained by the Sharpless catalytic asymmetric dihydroxylation of (E)-ArCR=CHAr' olefins, has been devised. The basis of the method is the transformation into the corresponding ketals with acetone. These derivatives can be resolved on the Daicel Chiralcel OD column, allowing the determination of the ee, while the absolute configuration is assigned by the analysis of their circular dichroism (CD) spectra and by the helicity of the cholesteric phase induced in nematic liquid crystals.