Collect. Czech. Chem. Commun. 1987, 52, 399-408

MO study of 2,2,4-trimethyl-2H-pyran, the simplest stable 2H-pyran derivative

Stanislav Böhm and Josef Kuthan

Department of Organic Chemistry, Prague Institute of Chemical Technology, 166 28 Prague 6


On the basis of MNDO optimized molecular geometries of the title compound I and its acyclic valence tautomers II and III it is demonstrated that the ability to isolate heterocyclic form I can be interpreted by its relatively lowest SCF-molecular energy calculated in MNDO or 4-31G, resp., orbital bases. Quantum chemical data are discussed in connection with the more general relation between the stability of 2H-pyran cycle and structural factors causing non-planarity of the equilibrium geometries of non-cyclic tautomeric structures.