Seddiki Khemissi
University Badji Mokhtar, Algeria
Title: Density Functional Theory Study of 1,3-dipolar cycloaddition and Solvent Effects
Biography
Biography: Seddiki Khemissi
Abstract
,3-dipolar cycloaddition reaction is the main method to obtain heterocyclic compounds in good yields.[1-3] Huisgen reaction using nitrone and olifins containing active double bonde such as maleimide, is widely used to synthesise five-membered heterocyclic derivatives like isoxazolidine.[4]
However, the current trend of organic synthesis is the use of green chemistry, and ecofriendly processes. [5] In this fact, recently, Bhaskar Chakraborty and Prawin K. Sharma reported a diastereo and regioselective synthesis of some novel isoxazolidine derivatives by one pot cycloaddition reactions between nitrone and different maleimides in aqueous phase. [6] The result has shown that form exo is more dominant.
The aim of our work is to study theoretically the stereoselectivity observed experimentally [6] which stipulate the exo isomers are major products of the reaction, and show the factors influence of this selectivity, the calculation was done with DFT theory functional density [7, 8] which include the electronic correlation, solvent effects were also used in this study.
The results of the energy ΔEr, the enthalpy ΔHr and the free enthalpy ΔGr of the reaction, the activation energy ΔE#, the enthalpy of activation ΔH# and the free activation enthalpy ΔG# at 298.15 K in the aqueous solution have shown that exo product is more favoured kinetically and thermodynamically than the endo product.
For the kinetic solvent effects of this reaction, among the four solvents used, water was found to be the best and the most convenient medium for the course of this reaction.