12. Alcohols, Ethers, Epoxides and Thiols

Propose a mechanism for each of the following reactions:

c.

When cis-2-methylcyclohexanol reacts with the Lucas reagent, the major product is 1-chloro-1-methylcyclohexane. Propose a mechanism to explain the formation of this product.

Explain the products observed in the following reaction of an alcohol with the Lucas reagent.

Neopentyl alcohol, (CH₃)₃CCH₂OH, reacts with concentrated HBr to give 2-bromo-2-methylbutane, a rearranged product. Propose a mechanism for the formation of this product.

Predict the product of the following reactions.

(a)

Predict the product of the following reactions.

(b)

Protonation converts the hydroxy group of an alcohol to a good leaving group. Suggest a mechanism for each reaction.

(a)

The reaction of tert-butyl alcohol with concentrated HCl goes by the S_N1 mechanism. Write a mechanism for this reaction.

Another method for converting alcohols to chloroalkanes makes use of chlorotrimethylsilane (TMSCl) and DMSO. Suggest a mechanism for this reaction to form (a) a 1° chloroalkane and (b) a 3° chloroalkane. [The reaction begins by the reaction of DMSO and TMSCl and is analogous to the Swern oxidation.]