THE INTRAMOLECULAR DIELS-ALDER VINYLFURAN (IMDAV) REACTION: A SHORT APPROACH TO AZA-ANALOGUES OF PINGUISANE-TYPE SESQUITERPENES Article Horak Y.I., Lytvyn R.Z., Homza Y.V., Zaytsev V.P., Mertsalov D.F., Babkina M.N., Nikitina E.V., Lis T., Kinzhybalo V., Matiychuk V.S., Zubkov F.I., Varlamov A.V., Obushak M.D. Tetrahedron Letters. Elsevier Ltd. Vol. 56. 2015. P. 4499-4501