CHEM 2443 Chapter Notes - Chapter 7: Activation Energy, Lewis Acids And Bases, Heterolysis (Chemistry)
Document Summary
Carbocations via reactions: a carbocation is formed in reaction sequence in which 2-methyl-2-chlorpropane (15) reacts with a lewis acid (alcl3), in the presence of potassium iodide (ki) to give 2-methyl-2-iodopropane (16) This transformation is explained by initial reaction of the electron-rich chlorine atom of 15 as a lewis base with the potent lewis acid alcl3. When the c-cl bond breaks, both electrons are transferred to aluminum (a heterolytic bond cleavage) leaving behind a positive charge on the carbon atom, which is carbocation. Note the arrow going from the electron-rich bond to fill the chlorine atom to the electron deficient aluminum in alcl3 to form cation 17 and the counterion, alcl4- Carbocation 17 is a reactive intermediate: alkyl halide 15 does not react with ki directly, but forms an initial transient product (17) that reacts with the iodide ion in a second chemical step.
