Regio‐ and Diastereoselectivity of 1,3‐dipolar Cycloaddition Reaction Between Sugar‐Derived Nitrile Oxides and <i>trans</i> ‐Ethylcinnamate: DFT and QTAIM Analysis

Abstract Various aspects of the 1,3‐dipolar cycloaddition between sugar‐derived nitrile oxides and trans ‐ethylcinnamate were analyzed using density functional theory. Frontier molecular orbitals reveal that the reaction follows normal electron demand, further supported by reactivity indices. Methyl cation/anion affinity was employed to demonstrate electron displacement. Topological parameters were analyzed at critical bond points, and non‐covalent interaction gradient isosurfaces were used to analyze the nature of the newly forming α‐bonds at transition state. Activation energy results align with experimental observations, demonstrating that the reaction is perfectly regioselective. However, electron density findings favor the opposite addition.