7. Substitution Reactions

Given the following reaction: ${\mathrm{CH}}_3\mathrm{Br}$ + $\mathrm{OH}-$ → ?, predict the major product of this $S{N}_2$ reaction.

Select the single best answer. Which $S{\mathrm{N}}_2$ reaction in the following pair is faster? (A) $\mathrm{CH}{3}_2\mathrm{CHBr}$ with $\mathrm{OH}-$ or (B) $\mathrm{CH}{3}_3\mathrm{CBr}$ with $\mathrm{OH}-$

Starting with an alkyl halide, how could the following compounds be prepared?

b. 1-methoxybutane

Which of the following is a property of the $S_{\mathrm{N}}2$ reaction mechanism?

You were told in [SECTION 7.11] that is best to use a methyl halide or a primary alkyl halide for the reaction of an acetylide ion with an alkyl halide. Explain why this is so.

Which of the following pairs of substrates will undergo an $S{N}_2$ reaction faster: (A) ${\mathrm{CH}}_3\mathrm{Br}$ vs. ${\mathrm{CH}}_3{\mathrm{CH}}_2\mathrm{Br}$, (B) ${\mathrm{CH}}_3{\mathrm{CH}}_2\mathrm{Br}$ vs. ${\mathrm{(CH}}_3{)}_2\mathrm{CHBr}$, (C) ${\mathrm{(CH}}_3{)}_2\mathrm{CHBr}$ vs. ${\mathrm{(CH}}_3{)}_3\mathrm{CBr}$?

Draw a transition state for the following substitution reaction.

The rate of the reaction of methyl iodide with quinuclidine was measured in nitrobenzene, and then the rate of the reaction of methyl iodide with ­triethylamine was measured in the same solvent. The concentration of the reagents was the same in both experiments.

c. Which alkyl halide has the larger k_quinuclidine/k_{triethylamine} ratio?

Which of the following best represents the product of an $S{N}_2$ reaction between ${\mathrm{CH}}_3{\mathrm{CH}}_2{\mathrm{Br}}_1$ (bromoethane) and $\mathrm{OH}-$ (hydroxide ion)?

Which SN2 reaction in the following pair is faster: (A) $\mathrm{CH}{3}_2\mathrm{CHBr}$ with $\mathrm{OH}-$ or (B) $\mathrm{CH}{3}_3\mathrm{CBr}$ with $\mathrm{OH}-$?

Predict the major product for the following SN2 reaction: ${\mathrm{CH}}_3\mathrm{Br}$ + ${\mathrm{OH}}_{-}$ → ?

For each pair of compounds, state which compound is the better S_N2 substrate.

a. 2-methyl-1-iodopropane or tert-butyl iodide.

b. cyclohexyl bromide or 1-bromo-1-methylcyclohexane

What nucleophiles would form the following compounds as a result of reacting with 1-iodobutane?

g.

Would you expect acetate ion (CH₃CO₂⁻) to be a better nucleophile in an S_N2 reaction with an alkyl halide carried out in methanol or in dimethyl sulfoxide?

Which of the following statements about the preparation of $\mathrm{ethyl} \mathrm{acetate}$ is correct with respect to the $\mathrm{SN}2$ reaction mechanism?