7. Substitution Reactions

Rank the following electrophiles from most reactive (1) to least reactive (4) in an SN2 reaction: $\mathrm{CH}{3}_{\mathrm{Br}}$, $\mathrm{CH}{3}_{\mathrm{CH}}{2}_{\mathrm{Br}}$, $\left(\mathrm{CH}{3}_2\right)\mathrm{CHBr}$, $\left(\mathrm{CH}{3}_3\right)\mathrm{CBr}$.

Which of the following alkyl halides is most likely to undergo rearrangement during reaction with ${\mathrm{CH}}^3\mathrm{OH}$?

Which of the following statements best describes a single-step bimolecular nucleophilic substitution reaction ($S_{\mathrm{N}}2$)?

Which of the following compounds will yield $\left(S\right)-2-bromopentane$ when treated with $PBr3$?

Which of the following molecules is most likely to undergo an $E1$ mechanism when stirred in methanol?

Which of the following is the major organic product when ${\mathrm{CH}}_{3}O-$ (methoxide) reacts with 2-bromopropane in ethanol, behaving primarily as a base?

Which of the following is the major product formed when 2-bromobutane undergoes a bimolecular elimination ($E_2$) reaction with a strong base?

Which of the following is the major product when 1-bromopropane reacts with $NaO{C}_1{H}_3$ in methanol under standard conditions?

Rank the relative rates of the following alkyl halides in an $S{N}_2$ reaction: $\mathrm{CH}{3}_{\mathrm{Br}}$, $\mathrm{CH}{3}_{\mathrm{CH}}{2}_{\mathrm{Br}}$, $\left(\mathrm{CH}{3}_2\right)\mathrm{CHBr}$, and $\left(\mathrm{CH}{3}_3\right)\mathrm{CBr}$.

What is the product of the nucleophilic substitution reaction when ${\mathrm{CH}}_3\mathrm{Br}$ reacts with $\mathrm{OH}-$ in aqueous solution?

Which of the following is the major organic product formed in an $S_1$ (SN1) reaction of $t_3\mathrm{-butyl}\mathrm{bromide}$ with water as the nucleophile?

The following functional-group interchange is a useful synthesis of aldehydes.

(c) Explain why a nucleophilic reagent such as ethoxide adds to an alkyne more easily than it adds to an alkene.

Which of the following is the major organic product formed when ${\mathrm{CH}}_3{\mathrm{CH}}_2\mathrm{Br}$ reacts with aqueous $\mathrm{NaOH}$ in a nucleophilic substitution reaction? Ignore any inorganic byproducts.

In a typical nucleophilic substitution reaction, what type of bond cleavage occurs when the leaving group departs from the substrate?

Which of the following alkyl halides is the most reactive substrate in an $E_2$ reaction?