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AbstractThe introduction of pin-up oxygen on C60, such as in the oxidized fullerenes C60O and C60On, induced noticeable increase in the antioxidant activity as compared to pristine C60. The water-soluble inclusion complexes of fullerenes C60O and C60Onreacted with linoleic acid peroxyl radical 1.7 and 2.4 times faster, respectively.

Bicyclic 3aH-cyclopentene[8]annulene-1,4-(5H,9aH)-diones underwent three types of acid-induced transannular reactions, Michael cyclization, [3+2] cycloaddition, and Friedel-Crafts ipso-alkylation, depending on the cyclopentenone ring substituent and the position of [8]annulenone substituent as well as the nature of acids. The Me-substituent permitted the Michael reaction for all acids used to give tricyclic diones by the activation of cyclopentenone carbonyl group.

The site selectivity switch in BF3-catalyzed dual skeletal rearrangements of cyclobutene-fused diaryl-homobenzoquinones is investigated by changing the stoichiometric amount of acid concentration. The observed selectivity profiles are simulated to elucidate factors that govern thermodynamic aspects and kinetic aspects.

The studies reported that irradiation of a homobenzoquinone derivative with various substituted alkenes and alkynes gave rise to the [2+2] photocycloadducts, tricyclic diones quantitatively as a mixture of regio-and stereoisomers. The studies concluded that a balance of repulsive steric hindrance and the attractive FMO interaction determines the stereochemical course of the [2+2] photoaddition of homobenzoquinone derivative with various substituted alkenes.

Research shows that the regio- and endo-selective [2+2] photocycloaddition of meta- and para-substituted homobenzoquinones with ethyl vinyl ether, under irradiation, leads to the [2+2] photoadducts, anti-tricyclic diones, regio- and endo-selectively in good yields.

Aroyl chlorides react with terminal alkynes which is attended by decarbonylation in the presence of a catalytic quantity of (RhC)(cod)2 and PPh3 to produce the corresponding vinyl chloride derivatives regio- and stereoselectively in good yields. The catalyst efficiency is dependent on the ratio of PPh3 to the rhodium species and good results are obtained when the PPh3/Rh ratio is 1.0. The product structures indicate that while the arylchlororhodium intermediate is also involved, arylrhodation to the alkynes, reinsertion of CO and intramolecular cyclization sequentially occur to produce indenones.

A simple one-pot reaction is described by using in situ chemically generated Na-naphthalenide as an electron reductant in the preferential generation of [C.sub.60.sup.2-]. The studies have shown a fast progressive formation of plausible 1,16-bisadduct-like intermediate moieties on a [C.sub.60] cage as the precursor structure that has led to the formation of EF-6M[C.sub.n] by considering the corresponding regiochemistry and electronic properties.

The kinetics of 1,3-dipolar cycloaddition of a series of meta- and para-substituted diphenyldiazomethanes (DDMs) with fullerenes C(Sub 60) and C(sub 70) as dipolarophiles are determined in toluene at 30 degree C in comparison with similar dipolar addition with TCNE, DDQ and chloranil (CA). The unexpected higher reactivity of fullerenes is described in terms of the inherent steric strain by the pyramidization of the sp(super 2) C-atoms as well as the shorter [6,6] bonds with larger pi-electron densities.

Lewis acid catalyzed rearrangements of cyclobutene-fused diphenylhomobenzoquinones with various acetylenes were investigated under the influence of AlCl3, SnCl4, BF3 and TiCl4. The factors that control the selectivity and the reactivity of the tandem reactions were analyzed based on the X-ray crystal analyses as well as the PM3 calculations.