Question 1

Provide the structure of the major organic product of the following reaction.

Accepted Answer

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Question 2

Which of the alkyne addition reactions below involves an enol intermediate? A)hydroboration/oxidation B)treatment with HgSO₄ in dilute H₂SO₄ C)hydrogenation D)both A and B E)both A and C

Accepted Answer

Both hydroboration/oxidation and treatment with HgSO4 in dilute H2SO4 involve enol intermediates that tautomerize to ketones or aldehydes.

Question 3

A mixture of 1-heptyne,2-heptyne,and 3-heptyne was hydrogenated in the presence of a platinum catalyst until hydrogen uptake ceased.If one assumes that the hydrogenation went to completion,how many distinct seven-carbon hydrocarbons were produced?
A)1
B)2
C)3
D)6
E)8

Accepted Answer

All three heptyne isomers will be fully hydrogenated to heptane, resulting in only one distinct seven-carbon hydrocarbon.

Question 4

Provide the structure of the major organic product(s)in the reaction below.

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Question 5

Provide the structure of the major organic product that results when 2-butyne is treated with HgSO₄/H₂SO₄ in water.

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Question 6

Provide the structure of the major organic product of the following reaction.

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Question 7

Provide the structure of the major organic product of the following reaction.

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Question 8

In the reduction of alkynes using sodium in liquid ammonia,which of the species below is not an intermediate in the commonly accepted mechanism?
A)vinyl anion
B)vinyl radical
C)radical anion
D)vinyl cation

Accepted Answer

The commonly accepted mechanism for the reduction of alkynes using sodium in liquid ammonia involves the formation of a radical anion intermediate, followed by the loss of a hydrogen atom to form a vinyl anion, which is then protonated to form a vinyl radical. The vinyl radical can then undergo further reduction to form a new radical anion intermediate, which can repeat the cycle. A vinyl cation is not involved in this mechanism, and is therefore not an intermediate in the reaction.

Question 9

The reagent needed to convert 2-butyne to trans-2-butene is A)H₂/Pt. B)H₂/Lindlar's catalyst. C)Li/NH₃. D)Na/NH₃. E)C or D.

Accepted Answer

Both Li/NH3 and Na/NH3 are used for the reduction of alkynes to trans-alkenes.

Question 10

An optically active compound (A),C₆H₁₀,reacts with H₂/Ni to produce compound (B),C₆H₁₄.(B)is optically inactive.Deduce the structures of (A)and (B).

Accepted Answer

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Question 11

Give the best reagents for the reaction. A)H₂SO₄,HgSO₄,HgSO₄ B)1)disiamylborane,2.HO^-,H₂O,H₂O₂ C)K₂Cr₂O₇,H⁺ D)NaOCl E)H₂,Pd

Accepted Answer

The reagents listed in option B (disiamylborane and H2O2 in H2SO4) are commonly used for hydroboration-oxidation reactions.

Question 12

Provide the structure of the major organic product of the following reaction.

Accepted Answer

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Question 13

Provide the structure of the major organic product(s)in the reaction below. CH₃CH₂-C C-CH₃

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Question 14

The reagent needed to convert 2-butyne to cis-2-butene is A)H₂/Pt. B)H₂/Lindlar's catalyst. C)Li/NH₃. D)Na/NH₃. E)H⁺/Zinc dust.

Accepted Answer

Lindlar's catalyst is used to convert terminal alkynes to cis-alkenes. In this case, 2-butyne is a terminal alkyne, and the desired product is cis-2-butene, making Lindlar's catalyst the best choice. The other options either do not lead to the desired product or are not commonly used for this specific transformation.

Question 15

Complete the following reaction.
3-hexyne

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3-hexyne ...

Question 16

Provide the structure of the major organic product(s)in the reaction below.

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Question 17

Give the major organic product for the reaction. A) B) C) D)CH₃CH₂CH₂CH CHOH E)

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Question 18

Provide the major organic product in the reaction below.

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Question 19

Complete the following reaction.

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Question 20

Provide the major organic product in the reaction below.

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Quiz 7: The Reactions of Alkynes - Introduction to Multistep Synthesis

Provide the structure of the major organic product of the following reaction.

Which of the alkyne addition reactions below involves an enol intermediate?

A mixture of 1-heptyne,2-heptyne,and 3-heptyne was hydrogenated in the presence of a platinum catalyst until hydrogen uptake ceased.If one assumes that the hydrogenation went to completion,how many distinct seven-carbon hydrocarbons were produced?

Provide the structure of the major organic product(s)in the reaction below.

Provide the structure of the major organic product that results when 2-butyne is treated with HgSO4/H2SO4 in water.

Provide the structure of the major organic product of the following reaction.

Provide the structure of the major organic product of the following reaction.

In the reduction of alkynes using sodium in liquid ammonia,which of the species below is not an intermediate in the commonly accepted mechanism?

The reagent needed to convert 2-butyne to trans-2-butene is

An optically active compound (A),C6H10,reacts with H2/Ni to produce compound (B),C6H14.(B)is optically inactive.Deduce the structures of (A)and (B).

Give the best reagents for the reaction.

Provide the structure of the major organic product of the following reaction.

Provide the structure of the major organic product(s)in the reaction below. CH3CH2-C C-CH3

The reagent needed to convert 2-butyne to cis-2-butene is

Complete the following reaction. 3-hexyne

Provide the structure of the major organic product(s)in the reaction below.

Give the major organic product for the reaction.

Provide the major organic product in the reaction below.

Complete the following reaction.

Provide the major organic product in the reaction below.

Provide the structure of the major organic product that results when 2-butyne is treated with HgSO₄/H₂SO₄ in water.

An optically active compound (A),C₆H₁₀,reacts with H₂/Ni to produce compound (B),C₆H₁₄.(B)is optically inactive.Deduce the structures of (A)and (B).

Provide the structure of the major organic product(s)in the reaction below. CH₃CH₂-C C-CH₃