Treatment of [Cl(dppe)(2)Ru-C=C-C=C-SiMe3] with [Fe(C5H5)(2)]PF6 leads to a
n unprecedented metal-assisted[2 + 2] coupling reaction on C-gamma=C-delta
bonds to obtain [Cl(dppe)(2)Ru-C=C-C=CHC(CH2)=C=C=Ru(dppe)(2)Cl]PF6 with th
e charge highly delocalized over seven carbon atoms and including a cyclobu
tenyl bridge; the crystal structure was solved.