Iron‐Catalysed Regio‐ and Stereoselective Head‐to‐Tail Dimerisation of Styrenes

Cationic iron salts and complexes catalyse the head‐to‐tail dimerisation of styrene derivatives to form the corresponding dimers with good to excellent yields and stereoselectivities. In particular, the use of a phosphine‐iron(III) complex allows the recovery and reuse of the catalyst. The counteranion plays an important role in both the activity and selectivity. These catalysts constitute an alternative to those based on toxic and expensive late‐transition metals.