Deck 5: Addition Reactions of Alkenes and Alkynes

Question 1

Complete the reaction by giving the missing reactant.

Answer 1

Question 2

Complete the reaction by giving the missing product.

Answer 2

Question 3

Complete the reaction by providing the missing starting material.

Answer 3

Question 4

Complete the reaction by giving the missing product.

Question 5

Complete the reaction by giving the missing product.

Question 6

Complete the reactions by giving the missing starting material, which is the same for both reactions.

Question 7

Complete the reactions by giving the structures of the missing organic products. (By-products are not shown.)

Question 8

Complete the reaction by giving the missing starting material.

Question 9

Consider the scheme.
a. Draw the structure of intermediate X, which has the formula shown under in the box provided.
b. What special kind of functional group is present in intermediate X?
c. What special kind of functional group is present in the product?

Question 10

Complete the reaction by giving the missing starting material.

Question 11

Give the structure of the enol intermediate in the hydration of 1-pentyne.

Question 12

Identify the reagents needed to transform isopentene to the product shown.

Question 13

A student allowed an alcohol, 4-penten-1-ol, to react with Br₂, expecting to observe a simple addition of Br₂ to the double bond. Instead, she isolated a compound X that proved to have the formula C₅H₉OBr. The reaction mixture from which X was isolated was very acidic.
Using mechanistic reasoning, including the curved-arrow notation, propose a structure for compound X. Show your logic at every step of the way! Your answer should explain why the reaction mixture became acidic.

Question 14

Complete the reaction by providing the structure of the missing product. (Ignore byproducts.)

Question 15

Complete the reaction by providing the structure of the missing starting material.

Question 16

Complete the reaction by providing the structure of the missing starting material.

Question 17

Consider the reaction, in which X is a stable, mercury-containing compound (not a reactive intermediate). Compound Y does not react with either Br₂, H₂/catalyst, or ozone.
a. What do you deduce about the structure of Y solely from its formula and the reactivity (or "unreactivity") data give? Explain briefly.
b. Use mechanistic reasoning to deduce the structure of X. Use the curved-arrow notation; show all relevant unshared pairs and charges. Then, using what you know about step (2)-no mechanisms!-deduce the structure of the product Y.

Question 18

Complete the reaction by providing a starting material with formula C₁₀H₁₆ that can give only the product shown at the right.

Question 19

Draw the structures of three enols that would be spontaneously converted into the following ketone. (Don't forget stereoisomers.)

Question 20

Complete the reaction by providing the structure of the missing product.

Question 21

Complete the reaction by providing the structure of the missing starting material.

Question 22

Compare the results of hydroboration-oxidation and Hg²⁺-catalyzed hydration for 2-butyne versus 1-butyne. For which is the result of the two reactions the same and which results are different?

Question 23

Devise a synthetic route for this conversion.

Question 24

Devise a synthetic route for this conversion.

Question 25

Devise a synthetic route for this conversion. Deuterium can be introduced by replacing the hydrogen in common reagents with its deuterium analog.