Organic Chemistry

Substituted Cyclohexanes: Axial and Equatorial Hydrogen Groups ❒The six-membered ring is the most common ring found among nature’s organic molecules. For this reason, we shall give it special attention. We have already seen that the chair conformation of cyclohexane is the most stable one and that it is the predominant …

  Conformations of Cyclohexane: The Chair and the Boat ❒ Cyclohexane is more stable than the other cycloalkanes we have discussed, and it has several conformations that are important for us to consider. (1) The most stable conformation of cyclohexane is the chair conformation. (2) There is no angle or torsional …

    ❒ Carboxylic acids are weak acids, typically having pKa values in the range of 3–5. Alcohols, by comparison, have pKa values in the range of 15–18, and essentially do not give up a proton unless exposed to a very strong base. ❒ To understand the reasons for this difference, let’s consider acetic acid …

     While formation of simple molecules could be explained adequately by overlap of atomic orbitals, the formation of molecules of Be, B and C present problems of greater magnitude having no solution with the previous theory. To explain fully the tendency of these atoms to form bonds and the …

    ❒ The strength of a Brønsted–Lowry acid depends on the extent to which a proton can be separated from it and transferred to a base. Removing the proton involves breaking a bond to the proton, and it involves making the conjugate base more electrically negative. Acidity within The …

    ❒ For a reaction to be practical, the equilibrium must favor the products, and the reaction rate must be fast enough to form them in a reasonable time. These two conditions depend on the thermodynamics and the kinetics of a reaction, respectively. ❒Thermodynamics describes energy and equilibrium. How …

  How To Predict the Outcome of Acid–Base Reactions  ❒The following table gives the approximate pKa values for a range of representative compounds.   ❒While you probably will not be expected to memorize all of the pKa values in the table , it is a good idea to begin to learn the …

Lewis Acids and Bases ❒ In 1923 G. N. Lewis proposed a theory that significantly broadened the understanding of acids and bases. ❒ As we go along we shall find that an understanding of Lewis acid– base theory is exceedingly helpful to understanding a variety of organic reactions. ❒ Lewis …

  Bond Dissociation Energy   ** Bond breaking can be quantified using the bond dissociation energy. **The bond dissociation energy is the energy needed to homolytically cleave a covalent bond.   ** The energy absorbed or released in any reaction, symbolized by ΔH°, is called the enthalpy change or heat …

  How To Use Curved Arrows in Illustrating Reactions   ** Up to this point we have not indicated how bonding changes occur in the reactions we have presented, but this can easily be done using curved-arrow notation. ** Curved arrows show the direction of electron flow in a reaction …