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Title: Kinetic and spectrophotometric investigation of the diels-alder reaction between maleic anhydride derivatives and substituted anthracenes in the presence of gallium and aluminum chlorides

Journal Article · · J. Org. Chem. USSR (Engl. Transl.); (United States)
OSTI ID:7170228

A comparison was made of the kinetic data for the normal Diels-Alder reaction of para-substituted N-arylmaleimides and substituted maleic anhydrides with meso-substituted anthracenes and of the reaction catalyzed by gallium and aluminum chlorides. The largely constant effects of gallium chloride (10/sup 4/) and aluminum chloride (10/sup 5/) in the acceleration of the reactions between the various pairs were demonstrated. The energies of charge transfer in the complexes between hexamethylbenzene and the dienophiles in the presence and absence of Lewis acids were determined by spectrophotometry. A significant decrease (to 1.2 eV) of the charge-transfer energy was found in the ..pi.., ..pi..-complexes and was attributed to the stabilization of the LUMO of the dienophile. From analysis of the obtained data it was concluded that the observed catalytic effect in the presence of Lewis acids can be explained by the approach of the frontier orbital levels and by a favorable change in the coefficients at the atomic orbitals responsible for the reaction.

Research Organization:
Lenin Kazan State Univ.
OSTI ID:
7170228
Journal Information:
J. Org. Chem. USSR (Engl. Transl.); (United States), Vol. 22:5,PT.2
Country of Publication:
United States
Language:
English