38328-65-3Relevant academic research and scientific papers
Anomeric effect enhancement in C-5-substituted 2-methoxytetrahydropyrans
Srivastava,Pavao,Seabra,Brown
, p. 51 - 58 (1997)
cis- and trans-2.5-Dimethoxytetrahydropyrans, cis-2,5-dimethoxy-6-methyltetrahydropyran and 2-methoxy-5-methyltetrahydropyran have been examined to see the effect of an OCH3 group at position 5 on the degree of anomeric effect in substituted 2-methoxytetrahydropyrans. The present study shows that this group stabilises the C-2 electronegative substituent in the axial position. Semi-empirical and ab initio molecular orbital calculations support this view, AM1 calculation gives lower enthalpies as well as lower dipole moments for the compounds having an OCH3 group in the axial position at C-2 over the equatorial form in 2-methoxytetrahydropyrans. This enhanced stabilisation is attributed to the electrostatic interaction between the partial positive charge at C-5 and the partial negative charge of the aglycone oxygen atom.
