Tetra-O-benzoylglucosylation: A New 1H Nuclear Magnetic Resonance Method for Determination of the Absolute Configuration of Secondary Alcohols

Article abstract of DOI:10.1021/jo00101a023

A new method for determination of the absolute configuration of secondary alcohols based on the anisotropic effect and glycosylation-induced 1H NMR shifts is described.The tetra-O-benzoyl-β-glucosylation of secondary alcohols induces dramatic shifts in the aglycon 1H NMR peaks.The differences between the proton chemical shifts of the D-glucosylated derivative and the free alcohol (Δδ = δ_D - δ_ROH) or more significantly between their chemical shifts in the D- and L-glucosylated derivatives (Δδ = δ_D - δ_L) are characteristic of the absolute configuration of the secondary chiral alcohol.Furthermore, in most cases the sign of the chemical shift difference of the carbinyl protons correlates with the absolute configuration of their carbons, namely positive or negative Δδ are obtained for (R)- or (S)-carbinyl carbons, respectively.Moreover, this method involves the use of one enantiomer and generally a single derivatization is sufficient.