8. Elimination Reactions

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

c. 1-bromo-2-methylcyclohexane + silver nitrate in water (AgNO₃ forces ionization)

Make models of the following compounds, and predict the products formed when they react with the strong bases shown.

(a)

Deuterium (D) is the isotope of hydrogen of mass number 2, with a proton and a neutron in its nucleus. The chemistry of deuterium is nearly identical to the chemistry of hydrogen, except that the C―D bond is slightly (5.0 kJ/mol, or 1.2 kcal/mol) stronger than the C―H bond. Reaction rates tend to be slower if a C―D bond (as opposed to a C―H bond) is broken in a rate-limiting step. This effect on the rate is called a kinetic isotope effect. (Review Problem 4-57)

b. When the following deuterated compound reacts under the same conditions, the rate of formation of the substitution product is unchanged, while the rate of formation of the elimination product is slowed by a factor of 7.

Explain why the elimination rate is slower, but the substitution rate is unchanged.

Show how you would prepare cyclopentene from each compound.

a. cyclopentanol

b. cyclopentyl bromide

Show how this 1° alcohol can be made from the following:

(a) a 1° alkyl bromide

S_N1 substitution and E1 elimination frequently compete in the same reaction.

a. Propose a mechanism and predict the products for the solvolysis of 2-bromo-2,3,3-trimethylbutane in methanol.

Suggest a bromoalkane and the conditions necessary to produce the alkenes shown.

(a)

Why is the S_N1 reaction shown an inefficient way of synthesizing ethers?

Of the three possible elimination mechanisms (Figure 12.50), this chapter focused on two of them (E1 and E2). The third possibility occurs in situations like the one below. What makes this mechanism favored under these conditions?