Homogeneous catalysis of olefin lsomerisation. Part VI. Pent-1-ene isomerisation catalysed by solutions of dodecacarbonyltri-iron(0) and of bis(benzonitrile)dichloropalladium(II) in benzene

Abstract

Isomerisation of pent-1-ene to cis- and trans-pent-2-ene is catalysed at 50 °C and above by solutions in benzene of Fe₃(CO)₁₂ and of PdCl₂(C₆H₅CN)₂. In both cases, preferential formation of trans-pent-2-ene occurs. Isomerisation of [1,2-²H₂]pent-1-ene reveals that each reaction proceeds by the intramolecular transfer of hydrogen and deuterium atoms. The reaction mechanisms involve π-allylic intermediates; for the palladium-catalysed reaction bis-π-allyl complexes may also participate.