1. You can write the two-step mechanism for the SN1 mechanism using the curved electron-pushing arrow formalism, and distinguish it from that for the one-step SN2 mechanism.
  2. You understand how to identify likely substrates for an SN1 reaction:  tertiary carbon or another structural feature that adds electron density to the carbocation;  presence of a very good leaving group (not alkoxide or hydroxide, but protonated  alcohol or water as LG is OK);  use of a polar solvent to promote ionization.
    Visualization: Carbocation Stabilization and SN1 Reactivity
  3. You understand that formation of the  carbocation can lead to stereochemical mixtures in the product when the nucleophile can attack different sides of the carbocation.  You can correctly specify the stereochemical outcome for any SN1 reaction.
    Visualization: Stereochemistry in substitutions
  4. You recognize the capacity for alkyl and hydride shifts (leading to more stable carbocations) in SN1 reactions.
  5. You know that in every substitution reaction, a competing elimination is going to occur.
    Visualization: LUMO of tBuCl
  6. You understand factors that may promote elimination:  steric inaccessibility of carbon; base (vs. nucleophile) strength; solvent polarity, overlap of C-H electrons with either empty p orbital (E1) or with the backside of the C-LG bond (E2).
  7. You know that eliminations usually follow the Zaitsev rule to give the more-substituted alkene.
  8. You understand the mechanistic requirement that E2 eliminations must adopt an anti-periplanar arrangement of H and halide for elimination, and the stereochemical consequences of this.
  9. You can apply the anti-periplanar requirement to eliminations from cyclohexane rings, including the impact of sterically demanding substituents on reactivity.

Recommended end-of-chapter problems:  7-25, 7-28, 7-30, 7-32, 7-35, 7-40, 7-42, 7-46, 7-53, 7-57, 7-60 .

Worked Problems:
Worked Problem 1
Worked Problem 2