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2023-2024 > Organic II - Ether, Epoxides and Thioethers > Flashcards

Organic II - Ether, Epoxides and Thioethers Flashcards

1
Q

Give formula for an ether.

A

R-O-R’

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2
Q

Are ethers symmetrical or unsymmetrical?

A

Both.

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3
Q

What is the structure and polarity of ethers? (hybridization, molecular geometry, angle and polarity)

A

O is sp3 hybridized, bent molecular geometry, C-O-C 110 degrees and polar C-O bond

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4
Q

Boiling point of ethers are similar to _______.

A

alkanes

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5
Q

Can ethers hydrogen bond with other molecules?

A

No

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6
Q

Ethers have a lower b.p than ________.

A

alcohols

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7
Q

Ether molecules can H bond with ______ & ________ molecules.

A

water; alcohol

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8
Q

Why are ethers used as solvents?

A

They can dissolve n.p and polar substances and are unreactive with strong bases.

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9
Q

-OCH3 is named as…

A

methoxy

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10
Q

Give the epoxide formula.

A

CH2-O-CH2

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11
Q

Define heterocyclic.

A

O is part of the ring

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12
Q

Oxetane is…

A

O + 3 C ring (forms a square)

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13
Q

Dioxane is…

A

2 O + 4 C (hexagon)

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14
Q

Furan is…

A

O + 4 C with 2 double bonds (dicyclopentene)

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15
Q

Pyran is…

A

O + 5 C with 2 double bonds (dicyclohexene)

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16
Q

Name all the heterocycles.

A

epoxide, oxetane, furan, pyran, dioxane

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17
Q

Another name for oxirane is…

A

1,2-epoxyethane

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18
Q

What method does the preparation of ether use?

A

Williamson ether synthesis

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19
Q

What are two common products of nucleophilic substitution?

A

Alcohols and ethers

20
Q

Can unsymmetrical ethers be synthesized two different ways?

A

Yes.

21
Q

Which path is preferred in Williamson ether synthesis?

A

Alkoxide attack less hindered alkyl halide.

22
Q

Why are phenoxide ions easily produced?

A

The alcohol proton is acidic.

23
Q

Phenyl halides or tosylates can’t be used in Williamson ether synthesis because…

A

They are poor substrates.

24
Q

MCPBA with a double bond usually forms…

A

an epoxide

25
Q

Formation of the chlorohydrin involves what? (reactant, intermediate, product)

A

alkene, chloronium ion, chlorohydrin enantiomers

26
Q

What are the reactants of the formation of chlorohydrin?

A

Cl2 and H2O

27
Q

What are the reactants of the displacement of chlorohydrin?

A

Base like OH-

28
Q

What does the displacement of chlorohydrin produce?

A

Epoxide, H2O and Cl- ion

29
Q

In base-catalyzed opening of epoxide, the base attacks the __________ carbon.

A

less substituted

30
Q

Opening an epoxide ring with HCl, Cl- attacks the ___________ carbon.

A

more substituted

31
Q

Define regioselectivity.

A

Ring opening of an epoxide with either a strong nucleophile or an acid (HZ)

32
Q

When opening an epoxide with a strong nucleophile, it attacks the ____ substituted carbon.

A

less

33
Q

When opening an epoxide with an acid, it attacks the ____ substituted carbon.

A

more

34
Q

Grignards and organolithiums open an epoxide ring by attacking the _____ hindered carbon.

A

less

35
Q

A primary alcohol reacting with H2SO4 and heat produces…

A

An ether and H2O

36
Q

Does a secondary alcohol (alkane) reacting with H2SO4 and heat produce an ether?

A

No. (Alkene with H2O)

37
Q

How to convert a poor leaving group to a good one on ethers?

A

Reaction with strong acids (ex. HBr and HI)

38
Q

What happens to the C-O bond of ethers reacting with HBr or HI?

A

C-O bonds are cleaved & 2 alkyl halides are formed.

39
Q

A branched structure (tertiary C-O bond) goes through _____ mechanism when cleaved.

A

SN1

40
Q

CH3-OH bond goes through ___ mechanism when cleaved.

A

SN2

41
Q

Phenyl ether cleavage produces what?

A

Phenol and an alkyl halide

42
Q

Give the standard formula for thioethers.

A

R-S-R’

43
Q

Name CH3-S-CH3.

A

Dimethyl sulfide

44
Q

Are thioethers easily synthesized by the Williamson ether synthesis?

A

Yes.

45
Q

_________ ion is used as the nucleophile in the synthesis of thioethers.

A

Thiolate

2023-2024 (16 decks)

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