Synthesis of ferrocenyl aryl ethers via Cu(I)/phosphine catalyst systems

Ferrocenyl aryl ethers can be synthesized in good yields by Cu(I)/phosphine-catalyzed coupling reactions from iodoferrocene or 1,1′-dibromoferrocene and various phenols in toluene, using Cs₂CO₃ or K₃PO₄ as a base. For the first time a solid-state structure of a ferrocenyl-1,1′-diaryl ether [1,1′-di(4-tert-butylphenoxy)ferrocene] has been determined from single-crystal X-ray data. The mixed ferrocenyl aryl ether 1-(4-tert-butylphenoxy)-1′-(2,4-dimethylphenoxy)ferrocene was prepared in a two-step synthetic protocol.