Deck 7: Reactions of Alkynes Introduction to Multistep Synthesis

Question 1

What is the common name for the following alkyne?

A)neohexyne
B)trimethylpropyne
C)trimethylacetylene
D)tert-butylacetylene
E)isopropylacetylene

Answer 1

tert-butylacetylene

Question 2

Give the IUPAC name for HCCCH₂CH₂CH₃.

Answer 2

1-pentyne

Question 3

What is the IUPAC name for the following compound?

A)cis, trans-2, 4-heptadiene
B)2Z,4Z-2, 4-heptadiene
C)cis, cis-2, 4-heptadiene
D)trans, trans-2, 4-heptadiene
E)2E,4E-2, 4-heptadiene

Answer 3

cis, trans-2, 4-heptadiene

Question 4

Name the following compound.

Question 5

Draw an acceptable structure for 3-sec-butyl-1-heptyne.

Question 6

Draw an acceptable structure for acetylene.

Question 7

Give the IUPAC name for (CH₃)₂C(CH₂CH₃)CCCH(CH₃)₂.

Question 8

Give the IUPAC name for BrCH₂CH₂CCCH₂CH₃.

Question 9

What is the IUPAC name for the following alkyne?

A)5-Bromo-2-heptyne
B)3-Bromo-5-heptyne
C)2-Bromo-2-methyl-4-hexyne
D)5-Bromo-5,5-dimethylhexyne
E)5-Bromo-5-methyl-2-hexyne

Question 10

How many distinct internal alkynes exist with a molecular formula of C₆H₁₀?

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

Question 11

Provide the structure of all distinct terminal alkynes with a molecular formula of C₆H₁₀.

Question 12

Provide an acceptable name for the compound shown.

Question 13

Write structures and give IUPAC names for all alkynes with molecular formula C₅H₈.

Question 14

Give the systematic name for the alkyne Cl₃CCH₂CH₂CCCH₃.

Question 15

How many distinct terminal alkynes exist with a molecular formula of C₅H₈?

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

Question 16

Draw an acceptable structure for 2-hexyne.

Question 17

Name the following compound.

A)3-heptyn-6-ol
B)3-hepten-6-ol
C)4-hepten-2-ol
D)4-heptyn-2-ol
E)4-heptan-2-ol

Question 18

Give the IUPAC name for the following compound.

A)isoprene
B)3-methyl-1,3-butadiene
C)2-methyl-1,3-butadiene
D)2-methyl-2,3-butadiene
E)isobutadiene

Question 19

Provide the systematic name of the compound shown.

Question 20

Give the systematic name of the compound shown below.

Question 21

Provide the systematic name of the compound shown.

Question 22

________ is produced when 1 equivalent of HBr is added to 1-hexyne in the presence of peroxides.

A)2-bromo-1-hexene
B)E-1-bromo-1-hexene
C)Z-1-bromo-1-hexene
D)a mixture of E and Z isomers of 1-bromo-1-hexene
E)E-2-bromo-2-hexene

Question 23

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

Question 24

Which of the following is the best synthesis of 2, 2-dibromopropane

A)
B)
C)CH₃C CH
D)
E)

Question 25

Which of the following statements correctly describes the general reactivity of alkynes?

A)An alkyne is an electron-rich molecule and therefore reacts as a nucleophile.
B)The σ bonds of alkynes are higher in energy than the π bonds and are thus more reactive.
C)Unlike alkenes, alkynes fail to undergo electrophilic addition reactions.
D)Alkynes are generally more reactive than alkenes.
E)Alkynes react as electrophiles, whereas alkenes reacts as nucleophiles.

Question 26

The carbon-carbon triple bond of an alkyne is composed of ________.

A)three σ bonds
B)two σ bonds and one π bond
C)one σ bond and two π bonds
D)three π bonds

Question 27

What are the hybridizations of the carbon atoms numbered 1 and 2 in the structure below? 1 2
H₃C-CH CH-C C-H

A)sp³, sp²
B)sp², sp²
C)sp², sp
D)sp, sp

Question 28

What is the major product of the following reaction? HCl
CH₃C CH

A)
B)
C)CH₃CH CH-Cl
D)
E)

Question 29

Which of the following statements is not true about propyne, HC C-CH₃?

A)It contains six sigma bonds.
B)It contains three pi bonds.
C)The H-C-H bond angle is about 109.5°.
D)The C-C-C bond angle is 180°.
E)The pi bond is weaker than the sigma bond.

Question 30

Name the following compound:

Question 31

What two atomic orbitals or hybrid atomic orbitals overlap to form the carbon-carbon σ bond in ethyne?

A)sp³-sp³
B)p-p
C)sp²-sp²
D)s-s
E)sp-sp

Question 32

Although you might expect 1-propyne to be more reactive than 1-propene in electrophilic addition reactions, the reverse is true. Explain this using your knowledge of the mechanism of electrophilic additions to both alkynes and alkenes.

Question 33

Which of the following compounds is the major product when 1-hexyne is treated with excess HBr?

A)1,1-dibromohexane
B)1,1-dibromohexene
C)1,2-dibromohexene
D)1,2-dibromohexane
E)2,2-dibromohexane

Question 34

Give the systematic name of the compound shown below.

Question 35

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

Question 36

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

Question 37

In the addition of hydrogen bromide to alkynes in the absence of peroxides, which of the following species is believed to be an intermediate?

A)vinyl anion
B)vinyl cation
C)vinyl radical
D)carbene
E)bromonium ion

Question 38

What are the hybridizations of the carbon atoms numbered 1 and 2 respectively in the following structure?

A)sp³, sp²
B)sp², sp²
C)sp, sp
D)sp², sp
E)sp, sp²

Question 39

Which of the following improperly describes the physical properties of an alkyne?

A)relatively nonpolar
B)nearly insoluble in water
C)less dense than water
D)insoluble in most organic solvents

Question 40

Provide the structure of (2E,4E)-2-chloro-2,4-octadiene.

Question 41

Provide the major organic product in the reaction below.

Question 42

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

Question 43

Provide the structure of the major organic produt that results when 2-butyne is treated with 1 equivalent of Br₂

Question 44

Provide the structure of the major organic produt that results when 2-butyne is treated with 2 equivalents of HCl.

Question 45

Give the major organic product for the reaction.

A)
B)
C)
D)CH₃CH₂CH₂CH CHOH
E)

Question 46

Provide the major organic product in the reaction below.

Question 47

Give the major organic product for the reaction.

A)
B)
C)
D)
E)

Question 48

Provide the major organic product in the reaction below.

Question 49

Which of the following are enol forms of 2-butanone,

A)
B)
C)
D)
E)

Question 50

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

Question 51

For the reaction below indicate whether the equilibrium constant will be greater than 1 or less than 1.
CH₃CH₂CHO ⇌ CH₃CH CHOH

Question 52

Provide the major organic product in the reaction below.

Question 53

Provide the structure of the intermediate which forms in the first step of the reaction of 1-butyne with water in the presence of H₂SO₄/HgSO₄.

Question 54

Provide the structure of the major organic produt that results when 2-butyne is treated with 1 equivalent of HCl.

Question 55

Provide the major organic product in the reaction below.

Question 56

Which of the following is the final and major product of this reaction?

A)I
B)II
C)III
D)IV
E)V

Question 57

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

Question 58

Give the major organic product for the reaction.

A)
B)
C)
D)
E)

Question 59

Which of the following is the final and major product of this reaction?

A)I
B)II
C)III
D)IV
E)V

Question 60

Provide the major organic product in the reaction below.

Question 61

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

Question 62

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

Question 63

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

Question 64

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

Question 65

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

Question 66

Complete the following reaction.

Question 67

Provide the major organic product in the reaction below.

Question 68

Complete the following reaction.
3-hexyne

Question 69

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

Question 70

Provide the major organic product in the reaction below.

Question 71

Give the major organic product for the reaction.

A)
B)
C)
D)CH₃CH₂CH₂CH CHOH
E)

Question 72

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

Question 73

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

Question 74

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

Question 75

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

Question 76

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

Question 77

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

Question 78

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).

Question 79

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

Question 80

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