The Studies of the Diels-Alder Reactions of 4,4’-Dimethoxylthiophenzophenone with Conjugated Diene Compounds

The energies and terminal coefficient of the FMO of 4,4’-dimethoxylthiobenzophenone （Ⅰ） were ealculated with CNDO/2 method. The regioselectivity and reactivity of Diels-Alder reactions of （Ⅰ） and trans-1-substituted-1,3-butadiene （Ⅱ） （trans-1-phenyl-1, 3-butadiene （ⅡA）, trans-2, 4-methyl pentadienoate （ⅡB）, trans-1, 3-pentadiene （ⅡC）） werw predicted by using FMO theory. The Diels-Alder reactions of （Ⅰ） and （Ⅱ） were studied. The rate constant K of these reactions measured at 60℃ and 70℃. The reactivity of experimental result of these cycloaddition reactions are consistent with the FMO theory. For the reasons of having small E_a values and the large negative ΔS^≠ values, these reactions are controlled by concerted mechanism and proceed rapidly.