12. Alcohols, Ethers, Epoxides and Thiols

When diethyl ether (CH₃CH₂OCH₂CH₃) is treated with concentrated HBr, the initial products are CH₃CH₂Br and CH₃CH₂OH. Propose a mechanism to account for this reaction.

What are the major products obtained when each of the following ethers is heated with one equivalent of HI?

c.

d.

What are the major products obtained when each of the following ethers is heated with one equivalent of HI?

e.

Propose a mechanism for each of the following reactions:

b.

Explain why HF and HCl cannot be used to cleave ethers in an S_N2 reaction.

What are the major products obtained when the following ether is heated with one equivalent of HI?

Explain why methyl propyl ether forms both methyl iodide and propyl iodide when it is heated with excess HI.

When ethyl ether is heated with excess HI for several hours, the only organic product obtained is ethyl iodide. Explain why ethyl alcohol is not obtained as a product.

Predict the products of the following reactions.

(b)

Predict the products of the following reactions.

(c)

Show an arrow-pushing mechanism that rationalizes formation of the two products. Which C―O bond will break first? Why?

Predict the alcohol and haloalkane that will form upon reaction of the ether shown with one equivalent of HBr. [Hint: Think carefully about which side will become the halide.]

Cleavage of the following ether produces the alcohol and haloalkane only, regardless of how much HBr is used. Thinking about the mechanism of the reaction, explain why bromobenzene is not also a product of this reaction.

Predict the products of the following reactions.

(a)