Mechanistic insights and antifungal assessment of (3+2) cycloaddition products of 2-diazopropane and 5-hydroxy-3-methyl-1,5-dihydropyrrol-2-one derivatives

The (3+2) cycloaddition reactions of 2-diazopropane with derivatives of 5-hydroxy-3-methyl-1,5-dihydropyrrol-2-one were investigated using Molecular Electron Density Theory. Calculations were performed at the wB97XD/6-311++G(d,p) level of theory. Conceptual Density Functional Theory indices revealed a low polar character for these reactions, supported by a minimal global electron density transfer at the transition structures, which were classified as forward electron density flux processes. The Electron Localization Function analysis identified 2-diazopropane as a pseudo(mono)radical three-atom component. It further indicated that bond formation does not start at the transition structures. Mechanistically, these reactions proceed via an asynchronous one-step mechanism, ultimately leading to products that are kinetically favored. Furthermore, molecular docking studies were conducted to evaluate the antifungal potential of the reaction products against pathogenic fungal strains, Candida albicans and Aspergillus fumigatus. The docking analysis assessed binding affinities and characterized molecular interactions between the proposed compounds and critical fungal proteins, highlighting their potential as antifungal agents.