The Diels - Alder reactions of furan and some derivatives with maleic anhydride
have been studied using methods of density functional theory (DFT): B3LYP, B3PW91,
MPW1PW91 and MPW1BPE with 6-31g(d) bases set and proceeding energy cor-relation
at M
P4 level of theory with same bases set. The results of this study showed that, for the
Diels - Alder reaction of Furan and 2-methyl furan with maleic anhydride, the reaction of
formation of exo-adduct proceeds under thermodynamical control, and the reaction of
formation of endo-adduct proceeds under kinatic control, but for the 2-furylmethanol, 2-
furylmethyl acetate and 2-furylmethyl benzoate, the reactions of formation of exo-adduct
proceed under thermodynamical and kinetic controls. The MPW1BPE/6-31g(d) level of
theory was advanced susceptible results by comparison with the reference experimental
data; exactly for furan-maleic anhydride Diels - Alder reaction.
Enthalpies of formation for three- and eight- membered heterocyclic ethers (15
compounds) in gas state have been determined by different theoretical methods: levels of
theory B3LYP/6-31g(d), MP2/6-31g(d) and chemical composite methods (Gn and CBS)
via two approach’s: atomization energy (AE) and bond separations (BS). Median absolute
deviations (MAD) and standard deviations (SD) of calculated values from experimental
data have been determined for every using method’s. The bond separation method has the
smallest MAD at most of theoretical methods in comparison to the atomization energy
approach. The 6-31g(d,p) basis set doesn’t seen clear effect in the theoretical results.
