9. Alkenes and Alkynes

Propose a mechanism for each reaction.

(c)

Propose a mechanism for each reaction.

(a)

Propose mechanisms for the following reactions. In most cases, more products are formed than are shown here. You only need to explain the formation of the products shown, however.

(b)

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

(a)

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

(c)

Show the product(s) you expect from dehydration of the following alcohols when they are heated in sulfuric or phosphoric acid. In each case, use a mechanism to show how the products are formed.

(c)

Write a mechanism that explains the formation of the following product. In your mechanism, explain the cause of the rearrangement, and explain the failure to form the Zaitsev product.

Predict the products of the sulfuric acid-catalyzed dehydration of the following alcohols. When more than one product is expected, label the major and minor products.

(d) 1-isopropylcyclohexanol

(e) 2-methylcyclohexanol

Propose mechanisms for the following reactions. Additional products may be formed, but your mechanism only needs to explain the products shown.

(b)

Four pairs of compounds are shown. In each pair, one of the compounds reacts more quickly, or with a more favorable equilibrium constant, than the less conjugated system. In each case, explain the enhanced reactivity.

(c)

Predict the product of the following pinacol rearrangements.

(b)

Propose a mechanism for each of the following reactions:

b.

Propose a mechanism for each of the following reactions:

a.

Propose a mechanism for each reaction.

(a)

(b)

Suggest an alkene that, in two steps, could be converted into each of the following ketones. Each sequence should involve a pinacol rearrangement.

(c)