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T‐shaped arrangements in the homodimers A and C of benzene and hexafluorobenzene, respectively, are rationalized by polar effects, but face‐to‐face stacking dominates in the 1:1 heterodimer B. The dynamics of a series of fluorinated 1,8‐diarylnaphthalenes clearly demonstrate the dependence of arene–arene interactions on the electronic characteristics of the arenes. The results are important for the design of supramolecular structures.

Two series of conformationally restricted polycyclic compounds (1-3 and 4-7) have been synthesized as model systems for studying the through-space interactions between face-to-face, center-to-edge (parallel-offset) oriented arenes. These compounds feature different X substituents on one of the interacting rings. By monitoring the variation of the delta Gz for the rotation around the aryl-aryl bond in 1-7 as a function of X by 2D [1H,1H] EXSY NMR spectroscopy, it was found that the barriers increase on passing from electron-donating to electron-withdrawing substituted derivatives. Quantum mechanical calculations [MP2/DVZ (2d,p)//B3LYP/DVZ(2d,p)] gave barrier values and variations in agreement with the experimental data. The results are consistent with a repulsive arene-arene interaction dominated by electrostatic effects.

Two chiral bisoxazolines (box) supported on a modified poly(ethylene glycol) (PEG) have been prepared by a reaction sequence that involved formation of the properly functionalized box and their attachment to the polymer matrix by means of a spacer and a linker. The solubility properties of PEG allowed use of the supported box as ligands in some catalytic asymmetric transformations carried out under homogeneous conditions and to recover the ligands as if bound to an insoluble support. When the supported box were employed in combination with Cu(II) salts in the Diels-Alder cycloaddition between cyclopentadiene and N-acryloyloxazolidinone, low levels of enantioselectivity were observed (up to 45% ee). Much better results were obtained in the cyclopropanation of styrenes carried out in the presence of CuOTf (up to 93% ee) and in the ene-reaction between alpha-methylstyrene or methylenecyclohexane and ethylglyoxalate (up to 95% ee). One of the ligands, readily recovered by precipitation and filtration, was recycled two times in the ene-reaction with marginal loss in the catalytic activity and very limited erosion of the enantioselectivity.