The quasi-homo-anomeric interaction in substituted tetrahydropyranyl radicals: Structure and kinetics of formation

Article abstract of DOI:10.1016/S0040-4020(98)00178-1

The EPR spectra of 3-acyloxytetrahydropyran-2-yl radicals (8 and 9) indicate that these species preferentially adopt conformations in which the orientation of the ester group allows maximum overlap between the SOMO, the lone pair on the ring oxygen, and the σ* orbital of C-O bond. These observations support earlier proposals that the same type of stabilising interaction affects the conformations of more complex glycosyl radicals. The rates of formation of 7 and 8 from the corresponding aryl sulfides are affected by this 'quasi-homo-anomeric' interaction.