THEORETICAL SECONDARY KINETIC ISOTOPE EFFECTS AND THE INTERPRETATION OF TRANSITION-STATE GEOMETRIES .2. THE DIELS-ALDER REACTION TRANSITION-STATE GEOMETRY

Theoretical secondary deuterium and primary C-14 kinetic isotope effects have been calculated for concerted and stepwise Diels-Alder reactions of butadiene with ethylene and acrolein. Comparisons between theory and experiment on substituted cases give definitive evidence for the mechanism and transition state geometries of the Diels-Alder reactions. Five levels of ab initio theory up to MCSCF/6-31G* are used for isotope effect calculations. The isotope effects for the retro-Diels-Alder reaction of ethanoanthracene are calculated and compared directly to experiment.