Not an oxygen‐bridged annulene (structural type 1) but rather an epoxide (structural type 2) is the product of the reaction of dimethyldioxirane with C60. In a competing reaction, a 1,3‐dioxolane (structural type 3) is formed—probably by a diradical mechanism. Cleavage of acetone from 3 leading to 2 was not observed at temperatures up to 110°C. Compound 3 could provide access to ring‐opened fullerenes.

The synthesis and characterization of sidewall‐functionalized SWNT derivatives (nPrNH)n‐SWNTs containing n‐propylamine addends is reported. The nucleophilic addition of in situ generated lithium n‐propylamide to the sidewall of SWNTs and the subsequent reoxidation of charged intermediates of the type (nPrNH)n‐SWNTn– leads to carbon nanotube derivatives with covalently attached amino groups. Based on the reaction sequence, a homogeneous dispersion of the carbon nanotube material is achieved as a result of the electrostatic repulsion of negatively charged intermediates. The solubility of the resulting propylamine‐functionalized (nPrNH)n‐SWNT material in organic solvents is drastically increased. The functionalized tubes were characterized in detail by Raman spectroscopy, thermogravimetric analysis (TGA/MS), X‐ray photoelectron spectroscopy (XPS) and UV/Vis/NIR spectroscopy. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)

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4-R-1,2,4-triazoline-3,5-diones (R = Me (MTAD), R = Ph (PTAD)) react stereospecifically with transcyclooctene (1) to give addition products 2,3, and 4. The products of the reaction and those obtained from nucleophilic trapping of the intermediate with methanol and water suggest an aziridinium imide followed by an open cation that can lead to transannular ring closure and hydride shifts. At -83 °C a frani-aziridinium imide intermediate is formed nearly quantitatively and can be directly observed via NMR spectroscopy. An activation energy of 16.2 kcal/mol was measured for the decomposition of the aziridinium imide. A mechanism is proposed for the reaction.

Intermolecular primary and secondary isotope effects on the ene reaction of /V-phenyl-1,2,4-triazoline-3,5-dione (PTAD) and singlet oxygen ('02) with deuterium-substituted (£)-2-methylbuten-2-oic (tiglic) acid methyl esters have been determined. In the case of '02, the primary isotope effect is 1.30-1.49 and the a and ß secondary isotope effects are near unity, consistent with a stepwise reaction path via a perepoxide intermediate, where the allylic hydrogen-abstraction step is rate determining. On the other hand, the existence of both primary (1.44) and inverse a and ß secondary isotope effects (0.91 and 0.77, respectively) in the PTAD reaction is consistent with either a concerted or a stepwise mechanism. Experiments in which both intermolecular primary and secondary isotope effects were measured at the same time suggest that, like singlet oxygen, PTAD reacts in a stepwise manner with the formation of the aziridinium imide intermediate (AI) in the rate-de-Contribution from the