12. Alcohols, Ethers, Epoxides and Thiols

a. Propose a mechanism for the following reaction:

Show how you would synthesize the following ethers in good yield from the indicated starting materials and any additional reagents needed.

(b) n-butyl phenyl ether from phenol and butan-1-ol

Suggest a phenoxide and an alkyl halide to make the following aryl alkyl ethers.

(b)

Provide the reagents necessary to carry out the following synthesis. What is the purpose of steps (a) and (e)?

Predict the product of the following reactions. [Two of them are Williamson ether syntheses. Why isn't the other?].

(c)

The compound shown below has three different types of OH groups, all with different acidities. Show the structure produced after this compound is treated with different amounts of NaH followed by a methylating reagent. Add a brief explanation.

(a) 1 equivalent of NaH, followed by 1 equivalent of CH₃I and heat

(b) 2 equivalents of NaH, followed by 2 equivalents of CH₃I and heat

(c) 3 equivalents of NaH, followed by 3 equivalents of CH₃I and heat

What is the best way to prepare the following ethers using an alkyl halide and an alkoxide ion?

c.

d.

In Chapter 12, we learned that crown ethers were used to increase the rate of S_N2 reactions (Assessment 12.80). Suggest a synthesis of 15-crown-5 using the reactions learned here in Chapter 13.

Design a synthesis for each of the following, using an intramolecular reaction:

a.

Show how the following ethers might be synthesized using (1) alkoxymercuration– demercuration and (2) the Williamson synthesis. (When one of these methods cannot be used for the given ether, point out why it will not work.)

a. 2-methoxybutane

b. ethyl cyclohexyl ether

c. 1-methoxy-2-methylcyclopentane