Cyclocarbonylation of acyclic 1,3-dienes via their tricarbonyl iron complexes: Cyclopenten-2-ones and dicarbonyl cyclopentadienyl iron halides

Article abstract of DOI:10.1016/S0040-4039(00)60188-0

Tricarbonyl iron complexes of acyclic 1,3-dienes can be converted to conjugated cyclopentenones by decomplexation with aluminium halides. Most complexes of simple dienes need drastic conditions for the cyclocarbonylation to occur (100 Atm CO, 100°C), with the exception of 1,1,3-trialkylbutadiene complexes which are nearly quantitatively converted into cyclopentenones at room temperature, even in the absence of a CO atmosphere. Under the same mild conditions, the other complexes lead in modest yields to cyclopentadienyl dicarbonyl iron halides by a cyclocarbonylation reaction followed by an aluminium halide promoted deoxygenation.