NMR differentiation of enantiomeric (+)- and (–)-α-pinene via complexation with cyclodextrins in water

Abstract

(+)- and (–)-α-Pinene form diastereoisomeric complexes with α-, 2,3,6-tri-O-methyl-β-, 2,3,6-tri-O-methyl-β- and 2,3,6-tri-O-acetyl-β-cyclodextrin which are distinguishable in ¹H and ¹³C NMR spectra, the α-pinene protons obeying the slow exchange condition during the complexation process; utilization of cyclodextrins as chiral shift reagents for molecules lacking polar groups is consequently proposed.