8. Elimination Reactions

Predict the product(s) that would result when molecules (a)–(p) are allowed to react under the following conditions: (vii) HCl; (viii) HBr; If no reaction occurs, write 'no reaction.'

(c)

Predict the product(s) that would result when molecules (a)–(p) are allowed to react under the following conditions: (v) 1. TsCl, Et₃N 2. NaOt-Bu (vi) H₂SO₄ If no reaction occurs, write 'no reaction.'

(f)

Predict the product(s) of the following substitution or elimination reactions, paying close attention to the stereochemical outcome of the reactions.

(a)

Predict the product(s) of the following substitution or elimination reactions, paying close attention to the stereochemical outcome of the reactions.

(d)

Predict the product(s) of the following substitution or elimination reactions, paying close attention to the stereochemical outcome of the reactions.

(e)

Given the reactants shown, what type of elimination would you expect to occur?

(b)

Show a mechanism for the following elimination reactions. Label the mechanism as E1 or E2.

(c)

Would you expect the following bases to favor E1 or E2 elimination?

(d) H₂O

Paying close attention to the stereochemical outcome, predict the product of these elimination reactions.

(c)

Indicate the type of catalysis that is occurring in the slow step in each of the following reaction sequences:

a.

Indicate the type of catalysis that is occurring in the slow step in each of the following reaction sequences:

b.

Why is melphalan a good cancer drug?

Indicate which species in each pair gives a higher substitution-product-to-elimination-product ratio when it reacts with isopropyl bromide:

c. Cl⁻ or Br⁻

The following three nitrogen mustards were studied for possible clinical use. One is now used clinically, one was found to be too unreactive, and one was found to be too insoluble in water to be injected intravenously. Which is which? (Hint: Draw resonance contributors.)

Finish Solved Problem 7-3 by showing how the rearranged carbocations give the four products shown in the problem. Be careful when using curved arrows to show ­deprotonation and/or nucleophilic attack by the solvent. The curved arrows always show ­movement of electrons, not movement of protons or other species.