Which alkyl halide from each of the given pairs reacts more rapidly in an elimination reaction? Provide a short explanation of your answer.

Explain why the following reaction produces only a substitution and no elimination products.

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.

For the following reaction, predict which elimination products will be formed. Identify the major product (if any).

cis-1-chloro-3-ethylcyclohexane + NaOC₂H₅ →

The reaction of (2R,3S)-3-bromo-2,3-diphenylhexane with NaNH2 in liquid NH3 yields three products: Two cis-trans isomers (A) and a pure isomer (B) . Another substance, (2S,3S)-3-bromo-2,3-diphenylhexane, under the same conditions gives a different cis-trans mixture (C) and a pure isomer (D). Determine the structures of all these products and explain why the two reactants produce two different pure isomers (B and D).

Provide the major products of the reaction of the alkyl halides below with HO^— via the E2 mechanism.

(a) Give the alkyl halide that will only form 2,4-dicyclopentylpent-3-ene as a product when it reacts with potassium tert-butoxide via the E2 mechanism.

(b) What is the required stereochemistry of the alkyl halide to form the following product?