1-Alkyl-2-(Z-1,2-diferrocenylvinyl)oxazolinium tetrafluoroborates: synthesis, characterization and nucleophilic ring opening

2,3-Diferrocenyl-1-ethoxycyclopropenylium tetrafluoroborate on reaction with 2-(alkylamino)ethanols at ∼80–82°C in the presence of triethylamine gives mixtures of novel 2-(1,2-diferrocenylvinyl) oxazolinium salts and 3,6-diaza-(E-2,3-diferrocenyl) acryloyl-3,6-dialkylheptanols. The oxazolidinium salts undergo heterocyclic ring-opening in the presence of N-nucleophiles to afford 2,3-diferrocenylacrylamide derivatives.