Chapter 12 Flashcards

Synthesis and Retrosynthesis

1
Q

What is a phenol?

A

a benzene + alcohol

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2
Q

What is a alkoxide?

A

deprotonated form of an alcohol

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3
Q

What is needed to form an alkoxide?

A

strong base
ex. NaH

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4
Q

How is acidity in alcohols determined?

A

Resonance - more resonance = increased acidity
Induction: presence of electron withdrawing groups increases acidity
Solvation: more poorly solvated (bulky)=acidic

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5
Q

What is the best way to make a 1 prime alcohol?

A

SN2

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6
Q

What is the best way to make 3 prime alcohols?

A

SN1

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7
Q

What are the three ways to prepare an alcohol from an alkene and which reagents do they use?

A
  • Acid-catalyzed hydration: Dilute H2SO4
  • Oxymercuration: 1)Hg(OAc)2, H2O
    2)NaBH4
  • Hydroboration: 1) BH3THF
    2)H2O2, NaOH
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8
Q

What is the order of oxidation?

A

alcohol to aldehyde/carbonyl to carboxylic acid

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9
Q

What are the common reducing agents?

A
  • NaBH4
  • LiAlH4
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10
Q

What is a diol compound?

A

compound with two hydroxyl groups

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11
Q

What are the Grignard reagents used to prepare and alcohol?

A

1)CH3MgBr, Et2O
2)H3O+
(CH3 can be any type of carbon chain)

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12
Q

What protects alcohol groups from modification in a Grignard rxn?

A

TMS (trimethylsilyl group)
TMSCl
———->
Et3N

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13
Q

What are the options for the substitution of primary alcohols?

A

1)Simple substitution: primary alcohol +HBr
2)Catalyzed substitution:
primary alcohol + HCl ZnCl2
———>

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14
Q

What are the options for the substitution of primary or secondary alcohols?

A

1) 2alcohol + TsCl/Pyr +Cl -
- inverts stereochemistry
2)1
alcohol +PBr3—-> OH substituted with Br
3)2* alcohol (SOCl2)/—–> Cl swaps with OH and is inverted

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15
Q

What are the methods for forming an alkene from the elimination of alcohols?

A
  • Acid-Catalyzed Elimination:
    3* alcohol (H2SO4)/—>/(delta Heat)
    via E1,
  • Base-catalyzed elimination
    TsCl/Pyr + EtONa (strong base)
  • E2 mechanism
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16
Q

What does the oxidation of 1* alcohol lead to?

A

Carboxylic acid

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17
Q

What does the oxidation of 2* alcohol lead to?

A

Ketone

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18
Q

What does the oxidation of 3* alcohol lead to?

A

Does not happen bc it would lead to 5 bonds to carbon

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19
Q

What are the four types of oxidation reactions?

A
  • Chromium Oxidation
  • controlled oxidation
  • swern oxidation
  • Dess-Martin Oxidation
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20
Q

Details of Chromium oxidation?

A

Reagents
- CrO3 or Na2Cr2O7
- (very strong oxidizers)
- 2* alcohol to ketone
- 1* alcohol is over oxidized to the acid

21
Q

Details of controlled oxidation?

A
  • reagent: PCC/CH2Cl2 (pyridinium chlorochromate)
  • stops at aldehyde
  • prevents over oxidation
22
Q

Details of stern oxidation?

A
  • Reagents: 1)DMSO, (COCl)2/2)Et3N
  • 2* alcohol to ketone
23
Q

Details of Dess-Martin Oxidation?

A

Reagents: DMP/CH2Cl2
- 1* alcohol to aldehyde

24
Q

What is an ether?

A

an oxygen connected to two hydrocarbon group

25
Q

What is the oxygen orbital hybridization of an ether?

A

sp^3
- electronic geometry is tetrahedral

26
Q

What is the molecular geometry of an ether?

A

bent (2 lone pairs)

27
Q

Intermolecular forces of neat ether

A
  • London forces
28
Q

What is the intermolecular force for ethanol?

A

hydrogen bonding

29
Q

Why do alcohols have a greater boiling point than ethers?

A

alcohols have stronger intermolecular forces than ethers

30
Q

What are the common ether solvents and what are their benefits?

A
  • Diethyl Ether
  • THF
  • 1,4-Dioxane
    Benefits:
  • Relatively unreactive
  • Low boiling point = easy to remove after a reaction
31
Q

What is a crown ether?

A

cyclic polyethers that tightly bind metal ions
Naming: X-Crown-Y

32
Q

How do ethers interact with metals?

A
  • Oxygen interacts with a metal, often stabilizing the negative charge
  • metals bind the center of ring by interacting with oxygens
  • hydrocarbons on the outside of the ring mask the positive charge of the metal
33
Q

How do crown ether produce a stable fluorine?

A

Crown ethers can produce stable F- to act as a nucleophile in an organic solvents (like benzene) because it overcomes issues of stability and solubility

34
Q

What ion do each of the crown ethers bind?
1) 12-Crown-4
2) 15 -Crown-5
3) 18- Crown-6

A

1)Li
2)Na
3)K

35
Q

What is Williamson Ether Synthesis

A
  • great for symmetrical and asymmetrical ethers
  • two step mechanism: Proton transfer and nucleophilic attack
  • uses a strong base that deprotonates the alcohol
    includes and alcohol and an alkyl halide
36
Q

What is autooxidation?

A
  • diethyl ether reacts slowly with O2 to form hydro peroxide which reacts violently when heated.
37
Q

What is an expoxide?

A

cyclic ether with a single oxygen

38
Q

What is an oxirane?

A

an epoxide that is particularly reactive due to ring strain

39
Q

What are the two common methods for forming epoxides?

A

1) Peroxy acid addition to an alkene
- trans alkene + MCBPA —->trans epoxide
2) Epoxides via halohydrins
- halohydrin is treated with a strong base Ex. NaOH

40
Q

Williamson Ether Synthesis Mechanism

A

(CH3OH) 1)NaH/2)CH3Br —> CH3OCH3

41
Q

Why are epoxides more reactive than ethers?

A

ring strain

42
Q

What are the two kinds of ring-opening reactions?

A
  • reaction with a strong nucleophile
  • acid-catalyzed ring opening
43
Q

Examples of some strong nucleophiles?

A

RONa, NaCN, NaSH, RMgBr, LAH

44
Q

When a strong nucleophile reacts with an epoxide ring, which carbon gets the addition of the nucleophile?

A

the less hindered carbon

45
Q

What happens to the stereochemistry when the ring is opened?

A

the stereochemistry is inverted

46
Q

If the ring has a primary and a secondary carbon which carbon does the nucleophile attach to?

A

the primary carbon

47
Q

If the ring has a primary carbon and a tertiary carbon, which carbon does the nucleophile attach to?

A

the tertiary carbon

48
Q

If the ring the ring has a secondary and a tertiary carbon, which does the nucleophile attach to?

A

the tertiary carbon

49
Q
A