Translocation of terminal olefins represents one strategy for repositioning this functional group within a molecule. Most methods for moving a terminal double bond require toxic or expensive transition metals, complex ligands, stoichiometric additives, or special reaction conditions.

Axel Jacobi von Wangelin and co-workers, University of Cologne, Germany, have reported the isomerization of allylbenzenes, 1-alkenes, isolated dienes, and (Z)-olefins with a cheap and non-toxic catalyst. Their optimized conditions, which used Fe(acac)₃ as the catalyst and phenylmagnesium halide as the reductant, required only two hours at room temperature to give the rearranged product in quantitative yield. The isomerization of linear 1-alkenes was highly selective, giving only 2-alkenes unlike many conventional methods which result in a thermodynamic mixture of internal alkenes.
This is a practical, cheap, and general olefin isomerization protocol that could be used in many fine chemical or pharmaceutical syntheses.

• Iron-Catalyzed Isomerizations of Olefins
  M. Mayer, A. Welther, A. Jacobi von Wangelin,
  ChemCatChem 2011.
  DOI: 10.1002/cctc.201100207