8. Elimination Reactions

For which of the following reactions would you expect elimination to be more favored than substitution?

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Silver-assisted solvolysis of bromomethylcyclopentane in methanol gives a complex product mixture of the following five compounds. Propose mechanisms to account for these products.

(e)

After a proton is removed from the OH group, which compound in each pair forms a cyclic ether more rapidly?

c.

Predict the products and mechanisms of the following reactions. When more than one product or mechanism is possible, explain which are most likely.

e. isobutyliodide + KOH in ethanol/water

f. isobutylchloride + AgNO₃ in ethanol/water

Draw the products of each of the following S_N2/E2 reactions. If the products can exist as stereoisomers, show which stereoisomers are formed.

c. (3S,4R)-3-bromo-4-methylhexane + CH₃O⁻

Write a balanced equation for each reaction, showing the major product you expect.

(d)

Given a secondary alkyl bromide reacting with a strong base such as $O_{2}H-$ (ethoxide ion) in ethanol, which mechanism is most likely to occur: $SN1$, $SN2$, $E1$, or $E2$?

Silver-assisted solvolysis of bromomethylcyclopentane in methanol gives a complex product mixture of the following five compounds. Propose mechanisms to account for these products.

(b)

For each of the following reactions, draw the major elimination product; if the product can exist as stereoisomers, indicate which stereoisomer is obtained in greater yield.

a. (R)-2-bromohexane + high concentration of CH₃O⁻

b. (R)-3-bromo-3-methylhexane + CH₃OH

For which of the following reactions would you expect elimination to be more favored than substitution?

(e)

Predict the products of the following reactions.

(c) benzyl bromide + sodium cyanide

Predict the products and mechanisms of the following reactions. When more than one product or mechanism is possible, explain which are most likely.

b. 2−chlorohexane + NaOCH₃ in methanol

Predict which of the following compounds will undergo elimination with KOH faster, and explain why. Predict the major product that will be formed.

Given the reactants shown, what type of elimination would you expect to occur?

(c)

Give the substitution and elimination products you would expect from the following reactions.

a. 3-bromo-3-ethylpentane heated in methanol