8. Elimination Reactions

What products will be obtained from the E2 reaction of the following alkyl halides?

a.

When the following reactions are carried out under the same conditions, the rate constant for the first reaction (k_H) is found to be 7 times greater than the rate constant for the second reaction (k_D). What does that tell you about the mechanism of the reaction? (Hint: a C—D bond is 1.2 kcal/mol stronger than a C—H bond.)

If a quaternary ammonium ion can undergo an elimination reaction with a strong base, why can’t a protonated tertiary amine undergo the same reaction?

Which of the following best describes the curved arrow notation for the $E2$ elimination mechanism when a strong base abstracts a proton from a $\beta$-carbon adjacent to a leaving group?

For the dehydrohalogenation ($E2$) reaction shown, which of the following statements is correct about the mechanism?

Which of the following statements correctly describes the major product formed in an $E_2$ elimination reaction of $2_{\mathrm{bromobutane}}$ with a strong base?

Which of the following reagents will favor an $E_2$ reaction with all substrates?

In the following compound, which of the labeled protons ($A$, $B$, $C$, or $D$) is most readily abstracted under $E_2$ conditions? (Assume the leaving group is positioned anti-periplanar to proton $B$.)

Which of the following is the major organic product formed when 2-bromobutane reacts with a strong base such as $O^{2}H-$ in an E2 elimination reaction?

Which of the following alkyl chlorides is most likely to undergo an $E_2$ elimination reaction when treated with a strong base?

Which of the following conditions will most likely promote an $E2$ reaction with an alkyl halide?

Which of the following alkyl chlorides will afford only a single alkene product ($A$) exclusively under $E2$ reaction conditions?

Which of the following is the major E2 product formed from the elimination of ${\mathrm{CH}}_3{\mathrm{CH}}_2{\mathrm{CH}}_2{\mathrm{Br}}_1$ (1-bromopropane) with a strong base?

Which of the following is the least reactive substrate in an $E_2$ reaction?

Which of the following organic bromides would undergo E$2_{}$ dehydrohalogenation to give $1_{}-{\mathrm{hexene}}_{}$ as the only alkene product?