Conversion of alkynes to cyclic imides and anhydrides using reactive iron carbonyls prepared from Fe(CO)5 and Fe3(CO)12

Alkyne–iron carbonyl complexes, prepared using Fe(CO)5–NaBH4–CH3COOH–amine–alkyne and Fe3(CO)12–amine–alkyne reagent systems, react with excess of amine at 25 °C to give cyclic imides in moderate to good yields. Further, unsaturated iron carbonyl species, prepared using the Fe(CO)5–pyridine-N-oxide system, react with alkynes to give the corresponding anhydrides.