Cleavage of a cyclotriphosphine ring by iron carbonyls

Fe(CO)5 in boiling toluene and Fe3(CO)12 in boiling benzene promoted the ring cleavage of tri-tert-butylcyclotriphosphine forming t-Bu3P3Fe2(CO)6. The product featured sterically hindered tert-butyl groups which reduced the chemical reactivity of the compound. The introduction of a chlorine atom at the center of the cyclotriphosphine intermediate replacing the diisopropylamino unit increased the accessibility of the compound to metal carbonyl intrusion.