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  2. Ring expansion and contraction - Wikipedia

    en.wikipedia.org/wiki/Ring_expansion_and_contraction

    A common method for expanding a ring involves opening cyclopropane-containing bicyclic intermediate. The strategy can start with a Simmons-Smith-like cyclopropanation of a cyclic alkene. [8] A related cyclopropane-based ring expansion is the Buchner ring expansion. The Buchner ring expansion is used to convert arenes to cycloheptatrienes. The ...

  3. Thermal rearrangement of aromatic hydrocarbons - Wikipedia

    en.wikipedia.org/wiki/Thermal_rearrangement_of...

    Benzene ring contractions are the last two mechanisms that have been suggested, and they are currently the preferred mechanisms. These reaction mechanisms proceed through the lowest free energy transition states compared to the diradical and dyotropic mechanisms. The difference between the two ring contractions is minute however, so it has not ...

  4. Cyclic compound - Wikipedia

    en.wikipedia.org/wiki/Cyclic_compound

    A cyclic compound or ring compound is a compound in which at least some its atoms are connected to form a ring. [1] Rings vary in size from three to many tens or even hundreds of atoms. Examples of ring compounds readily include cases where: all the atoms are carbon (i.e., are carbocycles),

  5. Aromatic ring current - Wikipedia

    en.wikipedia.org/wiki/Aromatic_ring_current

    A diagram of an aromatic ring current. B 0 is the applied magnetic field, the red arrow indicating its direction. The orange ring shows the direction of the ring current, and the purple rings show the direction of the induced magnetic field. An aromatic ring current is an effect observed in aromatic molecules such as benzene and naphthalene.

  6. File:Benzene Friedel-Crafts alkylation-diagram.svg - Wikipedia

    en.wikipedia.org/wiki/File:Benzene_Friedel...

    English: This is a diagram showing the reaction scheme of the Friedel–Crafts alkylation of benzene. The drawing was done in ACD/ChemSketch v12.01 (using standard ACS structure drawing style) and exported as a Windows Metafile (WMF). The image was converted to SVG using Inkscape v0.48.1 to yield a vector graphics version.

  7. Benzene - Wikipedia

    en.wikipedia.org/wiki/Benzene

    Benzene and cyclohexane have a similar structure, only the ring of delocalized electrons and the loss of one hydrogen per carbon distinguishes it from cyclohexane. The molecule is planar. [ 58 ] The molecular orbital description involves the formation of three delocalized π orbitals spanning all six carbon atoms, while the valence bond ...

  8. Benzyl group - Wikipedia

    en.wikipedia.org/wiki/Benzyl_group

    The term benzylic is used to describe the position of the first carbon bonded to a benzene or other aromatic ring. For example, (C 6 H 5)(CH 3) 2 C + is referred to as a "benzylic" carbocation. The benzyl free radical has the formula C 6 H 5 CH 2 •.

  9. Möbius aromaticity - Wikipedia

    en.wikipedia.org/wiki/Möbius_aromaticity

    Computed structure of trans-C 9 H 9 +, 2, illustrating the twisted nature of the ring, allowing incremental rotation of the orientation of p atomic orbitals around the ring: tracing the p orbitals all the way around the ring results in a phase inversion relative to the starting p orbital. The plane of the carbon skeleton (i.e., the nodal plane ...