On Structural Determination of C-7 Substituted 6,8-Dioxabicyclooctanes. A Reevaluation

Article abstract of DOI:10.1021/jo00333a014

The use of mass spectral and lanthanide shift reagent NMR data for structural elucidation in the 6,8-dioxabicyclo<3.2.1>octane series is examined.Sufficient irregularities associated with 7-substituted members of this series are found to prompt a cautionary response to their unconditional use in determining structures of these bicyclic ketals.A molecular mechanics calculational analysis of various members of the series examines how substituents affect the conformation of these ketals.CNDO/2 calculations to evaluate the Lewis basicity of the two ketal oxygens lead tothe conclusion that any preferential coordination will most likely find its origins in steric rather than electronic effects.