Elucidating the Selectivities and the Mechanism of [3+2] Cycloloaddition Reaction Between 9Α-Hydroxyparthenolide and 4-Methylbenzene-nitrile-oxide

Utilizing the Molecular Electron Density Theory, to survey the [2 + 3] cycloaddition processes between 4-methyl-Benzonitrile-N-oxide (1) and 9a-hydroxyparthenolide (2), reaction, activation energies and the reactivity indices are determined. An examination of conceptual DFT indices, 9a-hydroxyparthenolide (2) will provide in this reaction as an eletrophile, whereas 4-methyl-Benzonitrile-N-oxide (1) will share as a nucleophile. The reaction and activation energies clearly demonstrate that this cyclization is regio- chemo and stereospecific, which is in perfect agreement with the outcomes of the experiment. The mechanism of this [2 + 3] cycloaddition follows two steps mechanism, as indicated by ELF analysis.