Cycloaddition reactions of butadiene and 1,3-dipoles to curved arenes, fullerenes, and nanotubes: theoretical evaluation of the role of distortion energies on activation barriers.

Diels-Alder cycloadditions of butadiene and 1,3-dipolar cycloadditions of azomethine ylide, fulminic acid, and the parent nitrone to polyacenes, fullerenes, and nanotubes have been investigated with density functional theory and ONIOM methods. Activation barriers obtained for cycloaddition reactions on planar and curved systems have been shown to be highly correlated to the energy needed to distort the reactants to the geometry of the transition state (TS).