Synthesis and redox behavior of ene-diyne scaffolds that bear ferrocenes at the periphery

The ene-diyne systems 1 and 2 possessing ferrocenyl groups at the periphery were prepared by the simple one-pot Sonogashira-Hagihara coupling reaction of ethynylferrocene with 9-dibromomethylene-9H-fluorene (4) and 9,10-bis(dibromomethylene)-9,10-dihydroanthracene (5). The novel ferrocene-substituted ene-diyne compounds exhibited amphoteric redox behavior with a reversible one-stage electrochemical oxidation upon cyclic voltammetry.