Catalytic Isomerization of Olefins

The catalytic isomerization of olefins entails the selective relocation of carbon–carbon double bonds within an alkene substrate under the influence of a catalyst. This transformation allows the controlled conversion of terminal alkenes to internal alkenes or the interconversion of E/Z stereoisomers by modulating both the regio‐ and stereochemistry of the π‐bond. Metal‐based catalysts, ranging from precious metals such as ruthenium and rhodium to earth‐abundant alternatives including iron, cobalt and manganese, operate via well‐defined mechanistic pathways. These may involve migratory insertion and β‐hydrogen elimination steps, or reversible migratory chain‐walking along an alkyl chain. The choice of catalyst and ligand environment dictates the energy landscape, steering the equilibrium toward thermodynamically favoured isomers or kinetically trapped stereoisomers. Advances in ligand design, such as pincer frameworks and N‐heterocyclic carbenes, have enhanced catalyst stability, activity at low loadings and stereocontrol. Beyond fundamental interest in mechanism, olefin isomerization is exploited in petrochemical refining, fine‐chemical synthesis and polymer modification, offering atom‐economical access to value‐added intermediates from simple feedstocks.

Research from Nature Portfolio

Recent studies have demonstrated that parts‐per‐million loadings of ruthenium complexes can catalyse the highly selective chain‐walking of terminal alkenes to their internal counterparts. This process proceeds without solvent, ligand or protecting atmosphere, requiring only thermal activation above 150 °C. The catalyst transforms in situ into an active species capable of regioselective migration of the double bond and delivers internal alkenes in yields and selectivities exceeding 99%. The resulting products are immediately applicable in downstream reactions without further purification, underscoring the practical scalability and operational simplicity of this approach.

Catalytic Isomerization of Olefins publication trend

The graph below shows the total number of articles in catalytic isomerization of olefins across all publications each year (not limited to Nature Index journals).

Technical terms

Olefin: An unsaturated hydrocarbon containing at least one carbon–carbon double bond.

Catalytic isomerization: A process by which a catalyst facilitates the conversion of one isomer into another, often involving migration of bonds.

Chain‐walking: A sequence of migratory insertion and elimination steps that relocates a metal centre along an alkyl chain, shifting a double bond position.

β‐Hydrogen elimination: A mechanistic step in which a hydride is abstracted from the β‐carbon relative to a metal centre, forming an alkene.

Pincer complex: A metal complex featuring a ligand that binds in a tridentate manner, often enhancing catalyst stability and selectivity.

References

1. Parts–per–million of ruthenium catalyze the selective chain–walking reaction of terminal alkenes. Nature Communications (2022).
2. N2 Dissociation vs Reversible 1,2-Methyl Migration in PCNHCP Cobalt(I) Complexes in the Stereoselective Isomerization (E/Z) of Allyl Ethers. JACS Au (2024).
3. Switching between Hydrogenation and Olefin Transposition Catalysis via Silencing NH Cooperativity in Mn(I) Pincer Complexes. ACS Catalysis (2022).
4. Iron Catalyzed Double Bond Isomerization: Evidence for an FeI/FeIII Catalytic Cycle. Chemistry - A European Journal (2021).