Parts–per–million of ruthenium catalyze the selective chain–walking reaction of terminal alkenes

The chain–walking of terminal alkenes (also called migration or isomerization reaction) is currently carried out in industry with unselective and relatively costly processes, to give mixtures of alkenes with significant amounts of oligomerized, branched and reduced by–products. Here, it is shown that part–per–million amounts of a variety of commercially available and in–house made ruthenium compounds, supported or not, transform into an extremely active catalyst for the regioselective migration of terminal alkenes to internal positions, with yields and selectivity up to >99% and without any solvent, ligand, additive or protecting atmosphere required, but only heating at temperatures >150 °C. The resulting internal alkene can be prepared in kilogram quantities, ready to be used in nine different organic reactions without any further treatment. The chain-walking of terminal alkenes is an industrially relevant reaction. Here, the authors show that part-per-million amounts of a variety of ruthenium compounds catalyze the reaction in yields and selectivity up to >99%, without any solvent or additive.