Application of NMR spectroscopy of chiral association complexes. 14—chiral recognition of terpene and cyclohexene hydrocarbons by ¹H and ¹³C NMR

Abstract

Abstract Chiral NMR recognition of terpenic and similar hydrocarbons by Ag(fod) and optically active lanthanide shift reagents is described. Twenty‐four 1 H signals of eight compounds and, as a first report in the literature, eleven 13 C signals of three compounds were split into signal pairs due to the respective enantiomers. Although the magnitudes of the splittings are not connected to the structure of the substrate molecules in an obvious manner, the configurations of the similar compounds camphene and epi ‐β‐santalene were related empirically. All spectra were sufficiently resolved to allow separate integration of enantiomer signals; from the integrals the enantiomeric purities of seven non‐racemic mixtures were determined with good accuracy. The shift curves made several hitherto unknown assignments feasible.