The short route to chalcogenurea-substituted 3a,6-epoxyisoindoles via an intramolecular Diels-Alder furan (IMDAF) reaction. Antibacterial and antifungal activity

N-Furfuryl allylamines react with a broad range of isocyanates, isothiocyanates, isoselenocyanates with the formation of a 3a,6-epoxyisoindole core in one synthetic stage. The interaction sequence involves two consecutive steps: the nucleophilic addition reaction and the intramolecular Diels-Alder furane (IMDAF) reaction. The scope and limitations of the proposed method were thoroughly investigated, and it was revealed that the key [4+2] cycloaddition step proceeds through an exo-transition state, giving rise to the exclusive formation of a single diastereomer of the target heterocycle. Dynamic temperature NMR analysis allowed to fully investigating a case of coalescence of NMR signals and determined the coalescence temperature during the transition O → Se. The antimicrobial properties of the obtained compounds against sensitive strains of yeast Candida albicans, fungus Aspergillus niger and bacteria including Staphylococcus aureus, Micrococcus luteus, Pseudomonas fluorescens were identified. © 2024 The Royal Society of Chemistry.