Deck 8: Reactions of Alkenes and Alkynes

Question 1

Compare the products when the following compound reacts with Br₂ in the presence of an organic solvent versus water.

Answer 1

Organic solvent - bromination
Water - halohydrin formation In an organic solvent halogenation of the alkene will occur producing a halogenated alkane,while in water (another nucleophile)the product formed would be the halohydrin.

Question 2

How many isomeric products would be formed when the following compound undergoes dehydration?

A)1
B)2
C)3
D)4
E)5

Answer 2

5

Question 3

Instructions: Consider the reaction below to answer the following question(s).
Alkenes may be hydrated by the hydroboration/oxidation procedure shown.
Refer to instructions.The regiochemistry of hydroboration/oxidation of alkenes is:

A)Markovnikov.
B)non-Markovnikov
C)subject to solvent effects.
D)unrelated to alkene structure.

Answer 3

non-Markovnikov

Question 4

Predict the major product of the following reaction.

Question 5

What is the major product of this reaction?

Question 6

Predict the product of the reaction below.Indicate regiochemistry and stereochemistry if relevant.(D₂ = deuterium)

Question 7

On the structures provided,draw arrows showing the electron flow in the reaction mechanism for the electrophilic addition of hydrogen bromide to hex-1-yne.

Question 8

The reaction conditions to carry out the production of cyclopentene using bromocyclopentane as the starting material would be:

A)KOH,CH₃CH₂OH
B)H₂SO₄,THF
C)H₂O₂,OH^-
D)Hg(OAc)₂,H₂O

Question 9

Instructions: The reaction of 2-methylpropene with HBr in ether gives one of the two products below.Answer the following question(s)about this reaction.


Refer to instructions.Which product would have a lower energy transition state for the formation of the intermediate leading to it?

Question 10

The product(s)of the reaction when carried out in an organic solvent
Would be:

A)cis-1,2-dibromocyclohexane only
B)trans-1,2-dibromocyclohexane only
C)50/50 mixture of cis-1,2-dibromocyclohexane and trans-1,2-dibromocyclohexane only
D)mixture with > 50% being trans-1,2-dibromocyclohexane only

Question 11

Instructions: The reaction of 2-methylpropene with HBr in ether gives one of the two products below.Answer the following question(s)about this reaction.

Refer to instructions. The reaction mixture would contain a majority of which isomeric product?

Question 12

Instructions: For each reaction below,suggest structures for alkenes that give the indicated reaction products.There may be more than one answer.
Suggest structure(s):

Question 13

Which set of reagents is used for the Markovnikov addition of water to an alkene without rearrangement?

A)BH₃,THF followed by H₂O₂,NaOH
B)H₂O,H₂SO₄
C)Hg(O₂CCH₃)₂,H₂O followed by NaBH₄,NaOH
D)none of these

Question 14

Instructions: Consider the reaction sequence below to answer the following question.

Refer to instructions.Write the complete reaction mechanism for the first step of this reaction sequence.Show all electron flow with arrows and show all intermediate structures.

Question 15

Instructions: The reaction of 2-methylpropene with HBr in ether gives one of the two products below.Answer the following question(s)about this reaction.

Refer to instructions.Which product is the Markovnikov product?

Question 16

Instructions: Predict the products of each reaction below.Indicate regiochemistry and stereochemistry when relevant.
Predict and indicate:
a)
b) If the product of the above reaction were subsequently treated with periodic acid (HIO4), write the formula for the product formed.

Question 17

Instructions: To answer the question(s)below,consider the following reaction:
When cyclohexene reacts with chlorine in tetrachloromethane,the trans-dihalide is formed.

Refer to instructions.Write the complete,stepwise mechanism for this reaction.Show all intermediate structures and all electron flow using arrows.

Question 18

Instructions: Consider the reaction below to answer the following question(s).
Alkenes may be hydrated by the hydroboration/oxidation procedure shown.
Refer to instructions.The intermediate formed in the first step of this reaction is:

A)
B)
C)
D)

Question 19

Instructions: For each reaction below,suggest structures for alkenes that give the indicated reaction products.There may be more than one answer.

Suggest structure(s):

Question 20

Instructions: Predict the products of each reaction below.Indicate regiochemistry and stereochemistry when relevant.
Predict and indicate:

Question 21

What is the major organic product obtained from the following reaction?

Question 22

Draw all the isomeric products formed from the addition of HCl to the following compound.

Question 23

What type of reactive intermediate is involved in both of the following general reaction types?

A)carbocation
B)carbanion
C)radical
D)cyclic bromonium ion
E)cyclic ion

Question 24

What is the major organic product obtained from the following reaction?

Question 25

What type of reaction mechanism accounts for the reaction of an alkene with HBr to give an alkyl bromide?

A)nucleophilic addition
B)electrophilic addition
C)radical addition
D)elimination

Question 26

Draw the structure of the polymer formed from the monomer given below,showing four repeating units.

Question 27

What type of reaction mechanism is involved in the reaction of an alcohol with aqueous acid to give an alkene?

A)nucleophilic addition
B)electrophilic addition
C)radical addition
D)elimination

Question 28

Circle whichever of the following would be classified as a conjugated diene.

Question 29

What type of reaction mechanism accounts for the reaction of an alkyne with HBr to give an alkyl bromide?

A)nucleophilic addition
B)electrophilic addition
C)radical addition
D)elimination

Question 30

What is the major organic product obtained from the following reaction?

Question 31

What type of reactive intermediate is formed in the reaction of an alkene with aqueous acid to give an alcohol?

A)carbocation
B)carbanion
C)radical
D)carbene

Question 32

What is the best choice of reagents to perform the following transformation?

A)H₂O,H₂SO₄
B)HgSO₄;followed by NaBH₄
C)BH₃;followed by H₂O₂
D)OsO₄;followed by NaHSO₃

Question 33

What is the major organic product obtained from the following reaction?

Question 34

What type of reactive intermediate is formed in the reaction of an alkene with HBr to give a bromoalkane?

A)carbocation
B)carbanion
C)radical
D)cyclic bromonium ion

Question 35

Complete the following reaction

Question 36

Draw the structure of the monomer used to prepare the polymer shown below.

Question 37

What is the best choice of reagents to perform the following transformation?

A)H₂O,H₂SO₄
B)Hg(OAc)₂ and H₂O;followed by NaBH₄
C)BH₃;followed by H₂O₂,NaOH
D)OsO₄;followed by NaHSO₃