R. Radeglia et al., NMR SPECTROSCOPIC CHARACTERIZATION OF Z-E ISOMERS OF CYCLODODECA-1,5,9-TRIENE, Magnetic resonance in chemistry, 31(12), 1993, pp. 1054-1056
The four Z-E isomers of cyclododeca-1,5,9-triene were examined by C-13
NMR spectroscopy. The vicinal H-1-H-1 coupling constants of the olefi
nic protons were used to determine the stereochemistry at the double b
onds. For the symmetrically substituted -CH=CH- fragments (chemically
equivalent H atoms) this parameter was obtained from the C-13 NMR mult
iplets which are observed in H-1 continuous-wave off-resonance C-13 NM
R experiments. The precise assignment of the H-1 and C-13 chemical shi
fts, in particular for the Z,Z,E and Z,E,E isomers, was possible on th
e basis of off-resonance measurements in combination with C-13/H-1 het
eronuclear correlated and H-1/H-1-COSY-45 2D experiments.