A New Nine-Membered Triphosphorus Macrocycle

The first nine-membered triphosphorus macrocycles based on an o-benzobis(ethane-1,2-diyl) core have been prepared in high yield by the coupling of 1,2-diphosphinobenzene with trivinylphosphine on a cationic (η⁵-pentamethylcylopentadienyl)iron(II) template. Hydrogenation of the vinyl function followed by alkylation of the secondary phosphines gives the coordinated triethyl macrocycle, which has been structurally characterized.