<jats:title>Abstract</jats:title><jats:p>The total synthesis of the smallest cytochalasin isolated so far, periconiasin G, which bears a seven‐membered ring in lieu of the usual macrocycle, has been performed from both enantiomers of citronellal, relying on an intramolecular Diels–Alder reaction in favor of the natural <jats:italic>endo</jats:italic> stereochemistry. We show that, among the four synthesized stereoisomers, including the <jats:italic>exo</jats:italic> isomers, the one matching the NMR data of the natural product was not that assigned in the original report, imposing structure revision. The natural product, previously isolated from a plant‐mutualistic fungus, was biologically investigated taking into account its natural history, showing significant effects against the phytopathogenic fungus <jats:italic>Botrytis cinerea</jats:italic> and thus opening new opportunities in combating this pest.