Fullerene epoxides react with benzaldehyde derivatives in the presence of a pyridinium hexafluoroantimonate to give corresponding 1,3-dioxolane derivatives of [60]fullerene in excellent yields. The activation energy for the reaction of fullerene monoepoxide with benzaldehyde was determined to be 112.7 kJ mol−1. This result shows that fullerene epoxides undergo the stepwise SN1-like acetalization reaction.
Fullerene epoxides, C60On, having epoxide groups directly attached to the fullerene cage, constitute an interesting class of fullerene derivatives. In particular, the chemical transformations of fullerene epoxides are expected to play an important role in the development of functionalized fullerenes. This is because such transformations can readily afford a variety of mono- or polyfunctionalized fullerene derivatives while conserving the epoxy ring arrangement on the fullerene surface, as seen in representative regioisomeric fullerene polyepoxides. The first part of this review addresses the synthesis and structural characterization of fullerene epoxides. The formation of fullerene epoxides through different oxidation reactions is then explored. Adequate characterization of the isolated fullerene epoxides was achieved by concerted use of NMR and LC-MS techniques. The second part of this review addresses the substitution of fullerene epoxides in the presence of a Lewis acid catalyst. Most major substitution products have been isolated as pure compounds and their structures established through spectroscopic methods. The correlation between the structure of the substitution product and the oxygenation pattern of the starting materials allows elucidation of the mechanistic features of this transformation. This approach promises to lead to rigorous regioselective production of various fullerene derivatives for a wide range of applications.
Irradiation of 1-phenylcyclopentene, 1-phenylcyclohexene, and 2-phenylnorbornene in methanol, acetic acid-dioxan, and aqueous acetonitrile solution, with methyl p-cyanobenzoate or 1-cyanonaphthalene as sensitiser (electron-transfer) , gives fair to good yields of the product resulting from anti-Markovnikov addition of the nucleophilic solvent to the olefin.DIRECT or triplet sensitised irradiation of phenyl cyclic olefins, 1-phenylcyclopentene (I), 1-phenylcyclohexene (11) , and 2-phenylnorbornene (111) , in polar nucleophilic solvents, can lead to mixtures of the reduced olefin, polymer, and the Markovnikov addition pr0ducts.l In contrast we find electron-transfer photosensitised excitation of these olefins is a synthetically useful reaction for preparing the alcohol, ethers, and esters expected from anti-Markovnikov addition.Irradiation (medium-pressure mercury vapour lamp, Pyrex filter, 10') of an aqueous acetonitrile solution of (I)and 1-cyanonaphthalene (XV)t gave cis-(IV; 15%) and trans-2-phenylcyclopentanol (V; 27%). 2 From g.1.c. of the crude reaction mixture we estimated that <5y0 of any other adduct was present. When a similar irradiation was t The sensitiser was usually recovered ; however, in some cases (XV) was partially consumed to give l-cyano-3,4-dihydronaphthalene.$ New compounds (VI), (VII), (XIII), and XIV) gave satisfactory analysis or exact molecular weight for the parent-peak in the This is an expected product from (XV):. mass spectra. The structure of known compounds was confirmed by direct comparison (i.r.).
4-Vinylphenanthrene.-A mixture of 175 mg of methyltriphenylphosphonium bromide, 0.25 ml of 1.91 M phenyllithium, and 20 ml of dry ether were stirred and refluxed under nitrogen for 0.5 hr. A solution of 100 mg of 4-phenanthrenecarboxaldehyde in 20 ml of ether was added drop wise over a period of 15 min, and the mixture was then stirred and refluxed for 2 hr. The reaction mixture was filtered, the filtrate diluted with 200 ml of ether, washed with water, dried, and filtered, and the ether removed in vacuo.The residue was chromatographed on alumina using hexane as the eluent to give an oil which was further purified and analyzed via the picrate: 125 mg (59.1% yield), mp 112-113°.
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