STRUCTURE AND SPECTRAL PROPERTIES OF TWO NOVEL ISOMERIC 2,4-DIMETHYL-2-METHOXY-3,8-DIOXABICYCLOOCTANES

Article abstract of DOI:10.1016/S0040-4020(01)98927-6

The preparation and structure of the novel bicyclic ketals 5 and 6 is reported.A single crystal X-ray structure of compound 5 establishes the structures of 5 and 6. (1)H and (13)C NMR spectra are interpreted in terms of chair conformations for both 5 and 6, even though an unfavorable syn-diaxial interaction is present in 6.In the (1)H spectra, the axial C-4 proton of compound 5 absorbs downfield of its equatorial counterpart in 6.This is apparently due to a deshielding effect of the syn-diaxial C-2 methoxy group in compound 5.