Two different alkenes are obtained in the E2 elimination reaction between 2-chloro-3-phenylbutane and sodium methoxide. The major product is the Zaitsev product.

(i) When one pure stereoisomer of 2-chloro-3-phenylbutane reacts, only one pure stereoisomer of the major product is obtained. For example, the product obtained when (2R,3R)-2-chloro-3-phenylbutane reacts is the stereoisomer with the methyl groups cis. Explain the reason behind this stereospecificity using the Newman projection of the transition state.

(ii) Predict the major product of elimination of (2S,3R)-2-chloro-3-phenylbutane using the Newman projection of the transition state.

(iii) By taking into account the results in part (i), predict the major product from the elimination of (2S,3S)-2-chloro-3-phenylbutane.

No E2 reaction is observed when the following stereoisomer of 2-bromo-1,3,4-trimethylcyclohexane is treated with sodium methoxide. Explain this observation.

Hint: Examine if there is any hydrogen trans to the leaving group; then see if the two can have a diaxial relationship.

Determine the elimination products of the E2 reactions below. Can these products exist as stereoisomers?

i) (2R,3S)-2-bromo-3-ethylhexane + high concentration of CH₃O⁻

ii) (2R,3R)-2-bromo-3-ethylhexane + high concentration of CH₃O⁻

What is the arrow-pushing mechanism for the elimination reaction given below?

Classify the solvent below as polar protic, polar aprotic, or nonpolar.

Between the two haloalkanes below, which will react faster in S_N1 and E1 reactions?

i)

ii)

Which of the following species will have a higher ratio of S_N2 product compared to E2 product when it reacts with ethyl chloride in methanol: CH₃O⁻ or CH₃S⁻?

What product would be formed in the reaction of the following compound with the strong base?

The reaction shown below involves a step where the hydroxy group in the reactant is converted to a good leaving group via protonation. Propose a reasonable mechanism for the reaction.

Which of the following isomers is expected to be the least stable? The most stable?

In the absence of additional nucleophiles such as water or bromide ions, sulfuric acid can be utilized to isomerize less stable alkenes into their more stable counterparts. Give the mechanism for the acid-catalyzed isomerization of the reaction shown below.

Provide the dehydrohalogenation product(s) obtained when the molecule below is heated with 1 eq. of KOH in EtOH. Specify the major product(s) if applicable.

The major product when 2,2-dichloropentane is heated overnight with NaNH₂ at 150 °C has a formula of C₅H₈. Draw the structure of the product and provide the mechanism of the reaction.

Determine the mechanism of the synthesis that involves quenching with acid after the reaction of sodium acetylide and etiocholanolone.

Outline the synthesis of butane if 2-butyne is chosen as the starting material.

Provide the alcohol starting materials that react with phosphorus oxychloride in pyridine solvent (at 0 °C) to generate the alkenes shown below.

The majority of alkene synthesis results in the formation of the more stable trans isomer. Provide a reaction scheme for synthesizing henicos-7-ene from acetylene and other compounds that specifically produce the cis isomer.

Provide the synthetic step(s) required to complete the following conversion. (Ignore stereochemistry)

1-methylcyclohexanol → 2-bromo-1-methylcyclohexanol

At which carbon would an electrophile attach in hex-1-en-5-yne? Provide a reason.

Identify the product(s) that resulted from the reaction between the following molecule and HBr.

Provide the plausible mechanism for the given reaction.

Based on the experimental results of the oxymercuration-demercuration reaction, compare the stabilities of the carbocation and the mercurinium ion given below, and suggest why one is more stable than the other.

Show how the following transformation can be accomplished.
2-bromo-2-methylpentane → 2-methylpentan-3-ol

Give the products formed in the reaction below. Indicate which stereoisomers are formed if applicable.

(Z)-4,5-diethylnon-4-ene + H₂/Pt

Draw the products that will form from the reaction between the alkene below and with the following reagents: (i) Br₂ and (ii) I₂.