Theoretical study of the influence of phosphonate substituents on Diels-Alder reactions

A theoretical study of the effect of a phoshonate substituent on carbon-carbon double bonds is presented and its influence on the reactivity in Diels-Alder reactions commented. Energetic, structural and electronic effects on displacement reactions between various references and their substituted counterpart are investigated. Both, conventional 6-31G(d,p) Hartree-Fock (REF) and density functional theory (DFT), within the Becke's three parameter functional calculations are performed. Taking the cycloaddition of the butadiene on ethylene as reference, the influence of substitution at each position of reactants is discussed. For every possible substitution, reactants, transition states and products are obtained and analysed from a structural, energetic and electronic point of view. DFT and RHF results lead to the same conclusions. (C) 2002 Elsevier Science B.V. All rights reserved.