Efficient aldehyde olefination reactions catalyzed by an iron porphyrin complex in an ionic liquid

The commercially available complex Fe(TPP)Cl is an active and highly (E)-selective catalyst for the olefination of a variety of aldehydes in the presence of PPh3 and diazoacetate in the ionic liquid (bmim)(PF6). Dependent on the reactivity of the applied aldehyde, the reaction can be carried out at a reaction temperature of 50–80 °C. After 0.5–24 h quantitative olefin yields are reached with a broad variety of different aldehydes. Due to the application of an ionic liquid as reaction medium the products can be easily removed from the catalyst by a simple extraction and the catalyst is conveniently reusable without significant activity loss. Spectroscopic investigations indicate that the reaction mechanism includes the quantitative formation of a phosphorus ylide, which then reacts further in a Wittig reaction under formation of an olefin.