Iron-Catalyzed Mizoroki–Heck Cross-Coupling Reaction with Styrenes

In the presence of iron(II) chloride (FeCl2 ; 20 mol%) and potassium tert-butoxide (t- BuOK; 4 equiv.) in dimethyl sulfoxide (DMSO), aryl and heteroaryl iodides undergo stereoselective Mizoroki–Heck C—C cross-coupling reactions with styrenes at 60 8C giving the corresponding (E)-alkenes. The best yields are obtained upon adding a ligand (80 mol%) such as proline or picolinic acid. Aryl bromides and pyridinyl bromides are also coupled with styrenes but in lower yields.