Deck 14: Ethers, Epoxides, and Thioethers

Question 1

Provide the IUPAC name of the compound shown below.

Answer 1

1,1-diethoxycyclohexane

Question 2

Anisole is known by two other names. Give either of them.

Answer 2

methoxybenzene or methyl phenyl ether

Question 3

What is the complete systematic IUPAC name for the following compound?

A) 4-(1-methylethoxy)-4-isopropyl-4-methylpent-2-ene
B) 4-isopropyl-2,4-dimethylhept-5-en-3-ol
C) isopropyl-(4-isopropyl-4-methylbut-2-enyl) ether
D) (E)-4-isopropoxy-4,5-dimethylhex-2-ene
E) 4-isopropyl-4-methylbut-2-en-isopropyl ether

Answer 3

(E)-4-isopropoxy-4,5-dimethylhex-2-ene

Question 4

Provide a structural representation of oxetane.

Question 5

What is the hybridization of the oxygen atom in dialkyl ethers?

A) sp³
B) sp²
C) sp
D) s
E) p

Question 6

What is the correct IUPAC name for the following compound?

A) 3-methyl-3,4-epoxypentan-1-ol
B) 5-hydroxy-3-methyl-2,3-epoxypentane
C) 1-(2-hydroxyethyl)-1,2-dimethyloxirane
D) 3,4-epoxy-3-methylpentan-1-ol

Question 7

Which of the following corresponds to the COC bond angle in dimethyl ether?

A) 60°
B) 94°
C) 110°
D) 122°
E) 180°

Question 8

Which has the higher boiling point, diethyl ether or butan-1-ol? Briefly explain.

Question 9

Give two properties of ethers which allow them to be commonly used as solvents in organic reactions.

Question 10

Provide a structural representation of cis-3-ethyl-1,2-epoxycyclopentane.

Question 11

Provide a structural representation of 1,2-epoxybutane (also called 2-ethyloxirane).

Question 12

Provide a structural representation of 2-ethoxypentane.

Question 13

Draw structures which show the hydrogen bonding interaction that exists between water and dimethyl ether.

Question 14

Provide the structure of 3-methoxyfuran.

Question 15

Which of the following is not a true statement?

A) Dioxanes are six-membered ring ethers.
B) Furans are five-membered ring ethers.
C) Oxiranes are three-membered ring ethers.
D) Oxetanes are five-membered ring ethers.
E) Pyrans are six-membered-ring ethers.

Question 16

What complex results when BF₃ is dissolved in dimethyl ether?

Question 17

Provide a structural representation of 3-ethylfuran.

Question 18

Provide the structure of 4,4-dimethylpyran.

Question 19

Which of the following is not a property of ethers?

A) They dissolve a wide range of polar substances.
B) They have relatively high boiling points for their molecular weights.
C) They are nonhydroxylic.
D) They dissolve a wide range of nonpolar substances.
E) They are normally unreactive toward strong bases.

Question 20

Provide a structural representation of isopropyl tert-butyl ether.

Question 21

How could you synthesize this ether using an alkoxymercuration/demercuration reaction?

Question 22

Propose a structure for the ether of formula C₄H₁₀O with the following ¹H NMR signals:
δ 1.13 (doublet, 6H), 3.30 (singlet, 3H), 3.65 (septet, 1H) (ppm).

Question 23

What is the chemical shift of the carbon bound to oxygen in ethers in ¹³C NMR?

Question 24

Provide the major organic product in the reaction below.
CH₃CH₂CH₂OH
→

Question 25

Provide the structure of the fragment in the mass spectrum of dipropyl ether that results from a cleavage.

Question 26

This ether can be synthesized two ways using an alkoxymercuration/demercuration reaction. What are the two alkene starting materials that could be used?

Question 27

Which pair of reagents would produce the highest yield of (R)-2-ethoxybutane?

A) sodium (S)-2-butoxide + iodoethane
B) sodium (R)-2-butoxide + iodoethane
C) sodium ethoxide + (S)-2-iodobutane
D) sodium ethoxide + (R)-2-iodobutane
E) Both B and C would work equally well.

Question 28

Provide the major organic product in the reaction below.

Question 29

Propose a structure for the ether of formula C₄H₁₀O with the following ¹H NMR signals:
δ 0.95 (triplet, 3H), 1.52 (multiplet, 2H), 3.30 (singlet, 3H), 3.40 (triplet, 2H) (ppm).

Question 30

In mass spectrometry, what is the most common fragmentation of ethers?

Question 31

Provide an acceptable name for the compound shown below.

Question 32

Provide an acceptable name for the compound shown below.

Question 33

Which of the following is an acceptable way to synthesize t-butyl ethyl ether?

A) treatment of t-butyl bromide with sodium ethoxide
B) treatment of ethyl bromide with sodium t-butoxide
C) heating a mixture of ethanol and t-butanol in sulfuric acid
D) treating t-butyl bromide with Hg(OAc)₂
E) treating t-butanol with Hg(OAc)₂

Question 34

The Williamson ether synthesis occurs by the ________ mechanistic pathway.

Question 35

Propose fragmentations to account for the 59, 73, and 107 peaks in the MS of the ether below.

Question 36

Show the best method for preparing methoxycyclopentane via the Williamson ether synthesis.

Question 37

Provide an acceptable name for the compound shown below.
CH₃OCH₂CH(CH₃)₂

Question 38

How could you synthesize the ether below using a Williamson Ether synthesis?

Question 39

Propose a structure for the ether of formula C₄H₁₀O with the following ¹H NMR signals:
δ 1.20 (triplet, 6H), δ 3.45 (quartet, 4H) (ppm).

Question 40

Provide an acceptable name for the compound shown below.

Question 41

Provide the major organic product of the following.

Question 42

Show how propyl cyclopentyl ether can be prepared starting with cyclopentene and using an alkoxymercuration-demercuration route.

Question 43

Show the best method for preparing 4-propoxytoluene via the Williamson ether synthesis.

Question 44

Provide the major organic product of the reaction shown below.

Question 45

Show the reagents necessary to prepare 1-ethoxy-1-methylcyclopentane from 1-methylcyclopentene.

Question 46

Predict the major organic product of the following reaction.

Question 47

Unlike other functional groups, ethers often show an absorption in the fingerprint region of the IR spectrum between ________.

A) 600-800 cm^-1
B) 1000-1200 cm^-1
C) 1600 cm^-1
D) 3400 cm^-1

Question 48

Provide the major organic product of the following reactions.

Question 49

Provide the major organic product of the reaction shown below.

Question 50

When cyclohexene is subjected to mercuration in methanol and the resulting mixture is reduced with sodium borohydride, the major organic product is ________.

A) a meso ether
B) a 1:1 mixture of enantiomeric ethers
C) a meso diol
D) a 1:1 mixture of enantiomeric diols
E) methoxycyclohexane

Question 51

Which of the following reactions or series of reactions will lead to the formation of methoxycyclohexane?

A)
B)
C)
D)
E)

Question 52

When pent-1-ene is treated with mercury(II) acetate in methanol and the resulting product is reacted with NaBH₄, what is the primary organic compound which results?

A) 3-ethoxypentane
B) 1-methoxypentane
C) 1-ethoxypentane
D) 2-ethoxypentane
E) 2-methoxypentane

Question 53

Show the best Williamson ether synthesis for the following target molecule.

Question 54

Provide the major organic product of the following reactions.

Question 55

Provide the sequence of reactions by which propoxycyclohexane can be prepared through a Williamson ether synthesis.

Question 56

Provide the reagents that would complete the synthesis shown below.

Question 57

What is wrong with the following reaction?

Question 58

Provide the necessary reagents to complete the following reaction.

Question 59

Which of the following reactions is classified as a Williamson ether synthesis?

A)
B)
C)
D)
E)

Question 60

Provide the major organic product in the reaction below.
CH₃CH₂CH
CH<sub>2

→</sub>

Question 61

Which of the following compounds would undergo autoxidation most readily?

A) dibenzyl ether
B) MTBE
C) diethyl ether
D) isobutyl phenyl ether

Question 62

What are the expected products of the reaction of PhOCH₃ with concentrated HI?

A) phenol and methanol
B) phenol and iodomethane
C) iodobenzene and methanol
D) iodobenzene and iodomethane

Question 63

Provide the major organic product of the following reactions.

Question 64

Treatment of tetrahydrofuran with excess HBr results in the formation of what major organic product?

A) 1-bromobutane
B) 1,2-dibromobutane
C) 1,4-dibromobutane
D) 1-bromopentane
E) 1,5-dibromopentane

Question 65

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

Question 66

Provide two reasons why it would be difficult to prepare ethoxycyclopentane via an intermolecular dehydration route from ethanol and cyclopentanol.

Question 67

When hexan-1-ol is treated with conc. H₂SO₄ at moderate temperatures, ________ is formed via a(n) ________ mechanism.

A) di-n-hexyl ether; S_N2
B) di-n-hexyl ether; S_N1
C) di-n-hexyl ether; E2
D) di-n-propyl ether; E1
E) hex-1-ene; S_N1

Question 68

Di-n-pentyl ether can be converted to 1-bromopentane by treatment with HBr through essentially a(n) ________ mechanism.

A) S_N2
B) S_N1
C) E2
D) E1
E) ring opening

Question 69

Some ethers can be prepared by heating the appropriate alcohol in the presence of sulfuric acid. Can di-sec-butyl ether be prepared from sec-butanol by this route? Explain your answer.

Question 70

Provide the major organic product of the reaction shown below.

Question 71

The presence of what product of the autooxidation of ethers makes the distillation of ethers dangerous?

Question 72

When ethers are stored in the presence of oxygen, what explosive materials can result from autoxidation of the ether?

Question 73

Provide the major organic product of the following.

Question 74

Provide the major organic product of the reaction shown below.

Question 75

Predict the products of the following reaction and give a reasonable mechanism for their formation.

Question 76

What is the major organic product in the reaction below?

Question 77

Provide the major organic product in the reaction below.

Question 78

Provide the major organic product in the reaction below.

Question 79

Suggest a reasonable mechanism for the reaction shown below.

Question 80

Can one prepare di-sec-butyl ether in good yield by heating butan-2-ol in the presence of sulfuric acid? Explain.