9. Alkenes and Alkynes

What is the major product of the reaction?

What is the major product of the reaction?

What is the major product of the reaction?

What is the major elimination product obtained from the reaction of each of the following alkyl halides with hydroxide ion?

a. <IMAGE>

b. <IMAGE>

(••) Predict the major product(s) of the following elimination reactions, paying close attention to the stereochemical outcome of the reactions.

(b) <IMAGE>

a. What is the major product obtained when each of the following compounds undergoes an E2 reaction with methoxide ion? Show the configuration of the product.

b. Does the product obtained depend on whether you start with the R or S enantiomer of the reactant?

3. <IMAGE>

Which alkyl halide in each pair is more reactive in an E2 reaction with hydroxide ion?

a. <IMAGE>

b. <IMAGE>

Which alkyl halide in each pair is more reactive in an E2 reaction with hydroxide ion?

a. <IMAGE>

b. <IMAGE>

Which alkyl halide in each pair is more reactive in an E2 reaction with hydroxide ion?

c. <IMAGE>

d. <IMAGE>

For each of the following alkyl halides, indicate the stereoisomer that would be obtained in greatest yield in an E2 reaction.

c. 3-bromo-2,3-dimethylpentane

d. 3-bromo-3,4-dimethylhexane

For each of the following alkyl halides, indicate the stereoisomer that would be obtained in greatest yield in an E2 reaction.

d. 3-bromo-3,4-dimethylhexane

(••) Predict the major product(s) of the following elimination reactions, paying close attention to the stereochemical outcome of the reactions.

(e) <IMAGE>

For each of the following compounds, draw the product that forms in an E2 reaction and indicate its configuration:

a. (1S,2S)-1-bromo-1,2-diphenylpropane

When (1-bromoethyl)cyclohexane is heated in methanol for an extended period of time, five products result: two ethers and three alkenes. 

Predict which of the three alkenes is the major elimination product.

Predict the products of E1 elimination of the following compounds. Label the major products.

(a) <IMAGE>

(•••) When using sulfuric acid, but in the absence of other nucleophiles like water or bromide ion, less stable alkenes can be isomerized to their more stable isomer. Provide a mechanism for these acid-catalyzed isomerization reactions. [This is one illustration of the principle of microscopic reversibility.]

(b) <IMAGE>

For each of the following reactions, draw the major elimination product; if the product can exist as stereoisomers, indicate which stereoisomer is obtained in greater yield.

e.3-bromo-3-methylpentane+high concentration of CH3CH2O−

f. 3-bromo-3-methylpentane+CH3CH2OH