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  2. Butadiene - Wikipedia

    en.wikipedia.org/wiki/Butadiene

    Comparison of butadiene (s-trans conformer) and ethylene. The most stable conformer of 1,3-butadiene is the s-trans conformation, in which the molecule is planar, with the two pairs of double bonds facing opposite directions. This conformation is most stable because orbital overlap between double bonds is maximized, allowing for maximum ...

  3. Diels–Alder reaction - Wikipedia

    en.wikipedia.org/wiki/Diels–Alder_reaction

    A bulky substituent at the C2 or C3 position can increase reaction rate by destabilizing the s-trans conformation and forcing the diene into the reactive s-cis conformation. 2-tert-butyl-buta-1,3-diene, for example, is 27 times more reactive than simple butadiene.

  4. Rotamer - Wikipedia

    en.wikipedia.org/wiki/Rotamer

    Relative conformation energy diagram of butane as a function of dihedral angle. [9] A: antiperiplanar, anti or trans. B: synclinal or gauche. C: anticlinal or eclipsed. D: synperiplanar or cis. [2] Rotating their carbon–carbon bonds, the molecules ethane and propane have three local energy minima.

  5. Electrocyclic reaction - Wikipedia

    en.wikipedia.org/wiki/Electrocyclic_reaction

    When performing an electrocyclic reaction, it is often desirable to predict the cis/trans geometry of the reaction's product. The first step in this process is to determine whether a reaction proceeds through conrotation or disrotation. The table below shows the selectivity rules for thermal and photochemical electrocyclic reactions.

  6. Absolute configuration - Wikipedia

    en.wikipedia.org/wiki/Absolute_configuration

    The R/S system is an important nomenclature system for denoting enantiomers. This approach labels each chiral center R or S according to a system by which its substituents are each assigned a priority, according to the Cahn–Ingold–Prelog priority rules (CIP), based on atomic number.

  7. What are the deadliest plane accidents? See list after South ...

    www.aol.com/news/deadliest-plane-accidents-see...

    Two of the six Jeju Air crew members are the only survivors of the crash, and are being treated at a local hospital after the plane veered off a runway and slammed into a wall at Muan ...

  8. Majority of U.S. Teens Are Not Drinking, Smoking or Using ...

    www.aol.com/majority-u-teens-not-drinking...

    A national study discovered that teens in the United States consumed significantly less alcohol and drugs in 2024 compared to past years. Teen alcohol use has steadily decreased from 2000 to 2024 ...

  9. Hückel method - Wikipedia

    en.wikipedia.org/wiki/Hückel_method

    The theory predicts the molecular orbitals for π-electrons in π-delocalized molecules, such as ethylene, benzene, butadiene, and pyridine. [ 1 ] [ 2 ] [ 3 ] It provides the theoretical basis for Hückel's rule that cyclic, planar molecules or ions with 4 n + 2 {\displaystyle 4n+2} π-electrons are aromatic .