A PVCILO method has been used to compare the stabilization energies of the electron donor electron acceptor complexes between methyl vinyl ether as donor and the enophiles, 4-phenyl 1-1,2,4-triazoline-3,5-dione (1) and N-phenylmaleimide (2), respectively, as acceptor. A stabilization energry difference in favor of the more reactive 1 was obtained, which is being interpreted as an explanation for the enhanced rate of reaction of 1 vs 2, often by factors >10(4).