Benign Catalysis with Iron: Unique Selectivity in Catalytic Isomerization Reactions of Olefins

The use of noble metal catalysts in homogeneous catalysis has been well established. Due to their price and limited availability, there is growing interest in the substitution of such precious metal complexes with readily available and bio‐relevant catalysts. In particular, iron is a “rising star” in catalysis. Herein, we present a general and selective iron‐catalyzed monoisomerization of olefins, which allows for the selective generation of 2‐olefins. Typically, common metal complexes give mixtures of various internal olefins. Both bulk‐scale terminal olefins and functionalized terminal olefins give the corresponding products under mild conditions in good to excellent yields. The proposed reaction mechanism was elucidated by in situ NMR studies and supported by DFT calculations and extended X‐ray absorption fine structure (EXAFS) measurements. Stop—Further reaction not allowed! We present a general and selective hydrido triiron carbonyl cluster‐catalyzed mono‐isomerization of olefins, which allows for the selective generation of 2‐olefins, whereby classic acidic catalysts give mixtures of various internal olefins. The proposed reaction mechanism is supported by in situ NMR studies, DFT calculations, and EXAFS measurements.