Fullerene Derivatives Bearing a Phosphite Ylide, Phosphonate, Phosphine Oxide, and Phosphonic Acid: Synthesis and Reactivities

Treatment of phosphites (P(OR)(3)) and MeO(2)CCCCO(2)Me with C(60) affords the corresponding fullerene derivatives (1, R = Me; 2, R = Et; 3, R = n-Bu) consisting of a phosphite ylide group and a cyclopropane ring on the fullerene moiety in high yields. NMR data indicate that all phosphite ylides 1-3 exist as mixtures of E and Z isomers. Under similar reaction conditions, the reaction of phosphinite PPh(2)(OMe) and MeO(2)CCCCO(2)Me with C(60) gives ylide 4. Ylides 1-3 readily undergo hydrolysis with HBr to give corresponding phosphonates 5-7 in excellent yields, while ylide 4 reacts with hydrobromic acid to afford phosphine oxide 8. A mechanism is proposed to account for the formation of these phosphonate derivatives. Further treatment of phosphonate derivative 5 with trimethylsilyl iodide followed by water gave phosphonic acid derivative 9 in 83% yield.