Consider the following reaction. Which of the | vedclass

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(A) The reaction involves a secondary alkyl halide $(CH_3CH_2CH(Br)CH_3)$ reacting with a strong base/nucleophile,the acetylide ion $(HC \equiv C^-)$.

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$3-$Methylpent$-1-$yne

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(A) The reaction involves a secondary alkyl halide $(CH_3CH_2CH(Br)CH_3)$ reacting with a strong base/nucleophile,the acetylide ion $(HC \equiv C^-)$.Secondary alkyl halides with strong bases primarily undergo $E2$ elimination reactions rather than $S_N2$ substitution,due to steric hindrance.In this case,the acetylide ion acts as a base,abstracting a proton from the $\beta$-carbon to form alkenes.Elimination can occur at two different $\beta$-carbons:$1$. Removal of a proton from the $CH_3$ group (at $C_1$) leads to $pent-1-ene$.$2$. Removal of a proton from the $CH_2$ group (at $C_3$) leads to $pent-2-ene$,which can exist as $cis$ or $trans$ isomers.$S_N2$ substitution would lead to the formation of $3-methylpent-1-yne$. However,for a secondary halide,$S_N2$ is a minor pathway or suppressed by the $E2$ pathway.Among the options,$3-methylpent-1-yne$ is the substitution product,but the question asks what is not expected. Given the options,$3-methylpent-1-yne$ is formed via $S_N2$,but $pent-2-ene$ (specifically the $cis$ isomer) is a major elimination product. Actually,looking at the options provided,$3-methylpent-1-yne$ is the substitution product. Since the substrate is secondary,$E2$ is favored. Thus,the substitution product is the least expected.

Consider the following reaction. Which of the following products is not expected to be formed?
$CH_3CH_2CH(Br)CH_3 + HC \equiv C^- Na^+ \rightarrow ?$

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Consider the following reaction. Which of the following products is not expected to be formed?$CH_3CH_2CH(Br)CH_3 + HC \equiv C^- Na^+ \rightarrow ?$