Complete assignment of1H and13C NMR data and establishment of the relative stereochemistry of C-1-functionalized 2,4-dimethyl-8-oxabicyclo[3.2.1] oct-6-en-3-one derivatives

The total assignment of the 1H and 13C NMR spectra of 24 cis-endo and 15 cis-exo diastereoisomers of C-1-substituted 2,4-dimethyl-8-oxabicyclo[3.2.1]oct-6-en-3-one derivatives was deduced from the concerted application of DEPT, COSY, HETCOR, HMBC, HMQC and PS-NOESY experiments. The relative stereochemistry of major (cis-endo) and minor (cis-exo) diastereoisomers was established on the basis of correlation studies of their 1H and 13C NMR data.