Reactions of heterocyclic organotellurium compounds with triiron dodecacarbonyl: reactions of thiophenes revisited

Abstract

The reaction of thiophene and of benzothiophene with [Fe₃(CO)₁₂] was greatly accelerated by microwave heating when carried out in the presence of Fe₃O₄. Thus the same yields of products are obtained in 50 min as are achieved in 15–18 h of conventional heating; however no desulfurisation of the benzothiophene ring was observed. By contrast, both tellurophene and, more importantly, dibenzotellurophene undergo detelluration reactions with [Fe₃(CO)₁₂], the latter reaction affording a dibenzoferrole C₁₈H₈Fe₂O₆, the structure of which has been determined. The reaction of 2-telluraindane with [Fe₃(CO)₁₂] gave a complex C₁₉H₁₆FeO₃ in which a novel dimer of the detellurated C₈H₈ fragment is co-ordinated to an Fe(CO)₃ unit, as determined crystallographically. The released tellurium was isolated as either FeTe or as [Fe₃Te₂(CO)₉], depending on the reaction conditions.