7. Substitution Reactions

Which member in each pair in [PROBLEM 9-68] is a better leaving group?

e. I⁻ or Br⁻

f. Cl⁻ or Br⁻

Based on your answer to Assessment 12.8, which bases would you expect to be good leaving groups?

Formation of the carbocation should be fastest for which leaving group?

(a)

Formation of the carbocation should be fastest for which leaving group?

(b)

Which of the following is the better leaving group in a polar aprotic solvent?

(a) HO⁻ vs. F⁻

Which of the following is the better leaving group in a polar aprotic solvent?

(b)

Which is a better leaving group, HO⁻ or H₂O? Explain your answer.

In contrast to the results of Assessment 13.18, when a secondary haloalkane is treated with sodium ethanethiolate, we predict formation of a thioether. How is this rationalized?

A trifluoromethanesulfonate (triflate) can be used in a manner similar to tosylates. Which would you expect to be a better leaving group? Why?

Rank the following anions based on their stability as potential leaving groups. Explain your reasoning (1 = most stable ; 5 = least stable).

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

(c)

Formation of the carbocation should be fastest for which leaving group?

(c)

Which of the following is the better leaving group in a polar aprotic solvent?

(c) Br ⁻ vs. I ⁻

Which member in each pair in [PROBLEM 9-68] is a better leaving group?

a. H₂O or HO⁻

b. NH₃ or H₂O

Which member in each pair in [PROBLEM 9-68] is a better leaving group?

c. H₂O or H₂S

d. HO⁻ or HS⁻