Mohammad Zakarianezhad - Department of Chemistry, Payam Noor University, P. O. Box: 7815753613, Tehran, Iran

Stepwise reaction mechanism of the [2+3] cycloaddition reaction among alkyl isocyanides (contains tert-butyl isocyanide, cyclo hexyl isocyanide) with dialkyl acetylenedicarboxylate (contains dimethyl acetylenedicarboxylate, diethyl acetylenedicarboxylate and di-tert-butylacetylenedicarboxylate) in the presence of acetic anhydride was investigated both in the gas phase and in solvent was studiedtheoretically with B3LYP method using 6-311++G(d,p) basis set. The potential energy of all structures participated in the reaction path was evaluated. The geometry of all the structures participated during the reaction path, the rate-determining step, potential competitive routes during the reaction coordinate, structural effect and dielectric constant of the solvent, the effect of substituted alkyl groups on thepotential energy surfaces and the best product configuration were investigated based upon the quantum mechanical calculations. The effect of substituted alkyl groups on the potential energy surfaces was investigated. Also, the natural bond orbital method (NBO) applied for better understanding of molecular interaction.

Theoretical study, alkyl isocyanides, [2+3] cycloaddition, Reaction mechanism