PRINS REACTION UNDER MANGANESE DIOXIDE CONTROL: THE SYNTHESIS OF 6-OXA-2-AZABICYCLO[3.2.1]OCTAN-4-ONES FROM TETRAHYDROPYRIDINES AND FORMALDEHYDE Article Soldatenkov A.T., Polyanskii K.B., Temesgen A.W., Soldatova S.A., Sergeeva N.D., Kolyadina N.M., Lobanov N.N. Mendeleev Communications. Royal Society of Chemistry. Vol. 11. 2001. P. 27-29