Chapter 5 - Carbonyls and Alcohols Flashcards

1
Q

Acetal structure

A
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2
Q

Hemiacetal structure

A
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3
Q

Ketal structure

A
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4
Q

Hemiketal structure

A
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5
Q

Acid halide structure

A
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6
Q

Acid anhydride structure

A
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7
Q

Amide structure

A
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8
Q

Imide structure

A
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9
Q

Lactone structure

A
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10
Q

Lactam structure

A
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11
Q

Describe the signal present for a hydroxyl group on 1H NMR

A

broad peak between 1 and 5 ppm

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12
Q

Describe the general reactivity of alcohols

A

They are not good nucleophiles, but they can be deprotonated and converted into an alkoxide under basic conditions.

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13
Q

Describe the general reactivity of aldehydes and ketones

A

They are reactive with most nucleophiles , but not by a traditional nucleophilic substitution mechanism. The reactivity occurs mainly at the electrophilic carbonyl center, often forming a tetrahedral intermediate.

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14
Q

Out of ketals, hemiketals, acetals, and hemiacetals, which can be formed and removed under acidic conditions?

A

acetals and ketals

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15
Q

Out of ketals, hemiketals, acetals, and hemiacetals, which can be formed only under basic conditions, but removed under any conditions?

A

hemiacetals and hemiketals

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16
Q

What are the 4 steps in an acid-catalyzed mechanism?

A

1) protonate (making the leaving group a better leaving group)
2) break bond (leaving group leaves)
3) make bond (nucleophile attacks carbocation)
4) deprotonate (molecule returns to natural state)

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17
Q

What are the 4 steps in a base-catalyzed mechanism?

A

1) deprotonate (make a strong nucleophile)
2) make bond (nucleophile attacks), break bond (leaving group leaves)
3) protonate (molecule returns to neutral state)

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18
Q

What charge do intermediates carry in an acid-catalyzed mechanism?

A

positive

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19
Q

What charge do intermediates carry in a base-catalyzed reaction?

A

negative

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20
Q

The addition of an alcohol to an aldehyde under acidic conditions yields what?

A

an acetal

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21
Q

The addition of an alcohol to a ketone under basic conditions yields what?

A

a hemiketal

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22
Q

What reactant is needed to form a ketal or acetal protecting group?

A

a 1,2-diol (OHCH2CH2OH) under acidic conditions

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23
Q

What is produced when an ester is reacted with a strong base in water?

A

Saponification: forms a carboxylate (deprotonated carboxylic acid) + alcohol

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24
Q

What is produced when an ester is reacted with an acid in water?

A

Ester hydrolysis: carboxylic acid + alcohol

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25
Q

What is formed when a methyl ketone is reacted with I2 and strong base and water?

A

Iodoform reaction: carboxylate (deprotonated carboxylic acid) + I3CH (iodoform)

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26
Q

What is formed when an aldehyde is reacted with potassium permanganate (KMnO4) in strong base and water?

A

Oxidation: carboxylic acid

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27
Q

What is formed when a primary alcohol is reacted with potassium dichromate (K2Cr2O7) and acid in water?

A

Oxidation: carboxylic acid

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28
Q

What is formed when a secondary amide is reacted with a strong acid at high temperature?

A

Amide hydrolysis: carboxylic acid + RNH3+

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29
Q

What is formed when a nitrile is reacted with a strong acid at high temperature?

A

Nitrile hydrolysis: carboxylic acid + NH4+

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30
Q

What is formed when a carboxylic acid is reacted with thionyl chloride (SOCl2)?

A

acid halide

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31
Q

What is formed when a carboxylic acid is reacted with an alcohol and acid in high temperature?

A

transesterification: ester

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32
Q

What is formed when a carboxylic acid is treated with high temperature?

A

Condensation reaction: acid anhydride

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33
Q

What is formed when a carboxylic acid is reacted with 1) LiAlH4 (lithium aluminum hydride), 2) NH4Cl (ammonium chloride)?

A

primary alcohol

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34
Q

Why are esters more reactive than ketones/aldehydes?

A

They have an alkoxy (OR) leaving group.

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35
Q

What is formed when an ester is reacted with alcohol at high temperature under acidic conditions?

A

Transesterification: new ester with an alkoxy group from the alcohol

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36
Q

What is formed when a cyclic ketone is reacted with peroxyacids (RCO3H) (commonly mcpba)?

A

Baeyer-Villiger reaction: lactone

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37
Q

What is formed when an acid anhydride is reacted with water?

A

Hydrolysis: 2 carboxylic acids

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38
Q

Why are acid halides the most reactive of all the carbonyl groups?

A

They have the best leaving group.

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39
Q

What functional group makes up the peptide bond?

A

amide

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40
Q

What is formed when an amide is reacted with LiALH4 (lithium aluminum hydride)?

A

Reduction: amine

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41
Q

What functional group forms the hydrogen bond in base pairing of DNA and RNA?

A

amide

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42
Q

Carbonyl reactions can be categorized into what 3 categories?

A
  • attack at carbonyl carbon
  • deprotonation of alpha proton
  • oxidation/reduction
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43
Q

What are the 2 categories of reactions in which a nucleophile attackes the electrophilic carbonyl carbon?

A
  • substitution (leaving group)
  • addition (no leaving group)
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44
Q

What determines a carbonyl’s leaving group strength?

A

the pKa of its conjugate acid (good leaving groups have better stronger conjugate acids with low pKas)

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45
Q

decreasing order of reactivity for acid anhydride, acid halide, amide, ester

A

acid halide > acid anhydride > ester > amide

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46
Q

What forms in the deprotonation of alpha protons?

A

enolates

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47
Q

Enolate and Enol structures

A
48
Q

What are tautomers?

A

structural isomers that very in position of a pi bond and a hydrogen

49
Q

Keto-enol tautomerization

A
50
Q

carbonyl carbanion structure

A
51
Q

When a carbonyl carbanion is reacted with an alkyl halide, what happens?

A

The carbanion acts as a nucleophile to perform nucleophilic substitution, forming a new C-C bond and a longer ketone.

52
Q

What two bonding changes increase oxidation state?

A
  • gain of bonds to oxygen
  • loss of bonds to hydrogen
53
Q

What two bonding changes decrease oxidation state?

A
  • loss of bonds to oxygen
  • gain of bonds to hydrogen
54
Q

What is required for a carbon to be oxidized?

A

It must be bonded to oxygen and at least on hydrogen.

55
Q

How is oxidation state determined for each carbon in a molecule?

A

Electronegativity is analyzed.

Bonds to hydrogen give a negative to carbon and a positive to hydrogen. Bonds to oxygen give a positive to carbon and a negative to oxygen.

56
Q

Oxidizing agents are rich in what element?

A

oxygen

57
Q

Reducing agents are rich in what element?

A

hydrogen

58
Q

What results from the oxidation of a primary alcohol?

A

aldehyde ► carboxylic acid

59
Q

What results from the oxidation of an aldehyde?

A

carboxylic acid

60
Q

What results from the reduction of a carboxylic acid?

A

primary alcohol

61
Q

What results from the oxidation of a secondary alcohol?

A

ketone

62
Q

What results from the oxidation of a tertiary alcohol?

A

nothing, it cannot be oxidized

63
Q

What results from the reduction of a ketone?

A

secondary alcohol

64
Q

What is formed from the reaction of a primary alcohol with PCC (Collin’s reagent)?

A

Oxidation: aldehyde

65
Q

What is formed from the reaction of a secondary alcohol with potassium permanganate (KMnO4) and base?

A

Oxidation: ketone

66
Q

What is formed when an ester is reacted with 1) LiAlH4 (lithium aluminum hydride), 2) NH4Cl?

A

primary alcohol

67
Q

Which is more reactive: LiAlH4 or NaBH4?

A

LiAlH4

68
Q

What carbonyl compounds can NaBH4 reduce?

A

only aldehydes and ketones

69
Q

What carbonyl compounds can LiAlH4 reduce?

A

all carbonyl compounds

70
Q

What is formed by the reaction of an aldehyde/ketone with HCl/Zn(Hg)?

A

Clemmensen reduction: alkane

*must be acidic conditions

71
Q

What is formed by the reaction of an aldehyde/ketone with 1) HS(CH2)2SH, 2) Raney Ni

A

an alkane

72
Q
A
73
Q

What is formed by the reaction of an ester with NaBH4?

A

nothing, they do not react.

74
Q

What does the term hydride indicate?

A

hydrogen has a negative oxidation state

75
Q

What forms when an aldehyde reacts with a grignard nucleophile?

A

secondary alcohol

76
Q

What forms when a ketone reacts with a Grignard nucleophile?

A

tertiary alcohol

77
Q

What forms when carbonyls with a leaving group (esters, acid anhydrides, acid halides) reacts with a Grignard nucleophile?

A

tertiary alcohol (grignard adds twice)

78
Q

What is the best solvent for grignard reagents and why?

A

anhydrous ether solvent because grignard reagents are strong bases, so no protic hydrogens should be present

79
Q

What forms when carbon dioxide is reacted with a Grignard nucleophile?

A

carboxylic acid

80
Q

Describe an aldol condensation mechanism from start to finish

A
  • ketone/aldehydes’s alpha hydrogen is deprotonated
  • resulting carbanion attacks a second carbonyl compound, forming a hydroxy carbonyl compound
  • hydroxy carbonyl undergoes elimination under basic conditions to yield an α,β-unsaturated carbonyl
81
Q

When a ketone is asymmetric, what determines which side’s alpha hydrogen will be deprotonated in basic conditions?

A
  • Steric hindrance: less substituted side will be the kinetic product (lower Eact of transition state)
  • Greater stability: more substituted side will be thermodynamic product (more negative ΔGrxn)
82
Q

In an aldol condensation, which product will be favored if reacted with a strong, bulky base and low temperatures?

A

kinetic

83
Q

In an aldol condensation, which product will be favored when reacted with a strong, small base and high temperatures

A

thermodynamic

84
Q

In the fourth step of glycolysis, what enzyme breaks a six-carbon β-hydroxyketone into two three-carbon fragments (DHAP and G3P)?

A

aldolase

85
Q

How does the Claisen condensation differ from an aldol condensation?

A

An ester is used rather than a ketone or aldehyde. Since it has a leaving group, it is a substitution reaction rather than an addition reaction.

86
Q

What reaction is involved in fatty acid synthesis between thioesters?

A

claisen condensation

87
Q

What is the general result of transesterification?

A

conversion of one ester into another by exchanging the alkoxy group, in either acidic or basic conditions

88
Q

What is the result of saponification of triglycerides?

A

They are broken down into glycerol and fatty acids

89
Q

What reaction is responsible for the conversion of fatty acids and glycerol into fatty acids?

A

transesterification

90
Q

What is the general result of the Wittig reaction?

A

It converts a carbonyl into an alkene using phophonium ylide

91
Q

What is the general result of a pinacol rearrangement?

A

conversion of a vicinal diol into a ketone by alkyl migration, which converts a tertiary carbocation into a resonance stabilized carbocation, in acid

92
Q

What is the general result of an iodoform reaction?

A

methyl ketone reacts with iodine (I2) in the presence of a strong base, producing a carboxylate and iodoform

93
Q

What are the results of an iodoform test if it is positive?

A

It will be a yellow precipitate, meaning the reactant was a methyl ketone.

94
Q

What is the general result of the Wolff-Kishner reduction?

A

conversion of a ketone/aldehyde into an alkane using 1) hydrazine, 2) aqueous hydroxide

*must be basic conditions

95
Q

Hydrazine structure

A
96
Q

PCC structure

A
97
Q

What is a typical protecting group of ketones?

A

ketals

98
Q

What is a typical protecting group of aldehydes?

A

acetals

99
Q

What is a typical protecting group of alcohols?

A

silyl ether

100
Q

What is the pKa of alpha protons in the middle of acetoacetic ester/malonic ester?

A

~11

101
Q

acetoacetic ester structure

A
102
Q

Malonic ester structure

A
103
Q

When a β-ketoacid is heated, what results?

A

Decarboxylation: carbon dioxide + tautomerized enol/ketone

104
Q

Is anabolism reductive or oxidative? Does it build up or break down a moledule?

A

reductive, build-up

105
Q

Is catabolism reductive or oxidative? Does it build up or breakdown a molecule?

A

oxidative, breakdown

106
Q

Where do reductions normally take place physiologically? What is one exception?

A

in the cytoplasm, with the exception of glycolysis

107
Q

What are the two most common biological reducing agents?

A

NADH, FADH2

108
Q

What are the two most common biological oxidizing agents?

A

NAD+, FAD

109
Q

What is FADH2’s biochemical role?

A

hydrogenation of pi bonds

110
Q

What is acetal coenzyme A’s biochemical role?

A

transfer of an acetyl group to a biological species

111
Q

What is formed from the reaction of an alcohol with SOCl2 (thionyl chloride)?

A

alkyl halide (X = Cl)

112
Q

What is formed from the reaction of alcohol with PBR3?

A

alkyle halide (X = Br)

113
Q

What is a possibility when malonic ester is reacted with a reactant that has two nucleophilic sites?

A

it may cyclize

114
Q

Where do oxidations normally take place physiologically?

A

in the mitochondrial matrix

115
Q

acetate structure

A
116
Q

What is formed when a carboxylic acid is reacted with SOCl2 (thionyl chloride)?

A

acid chloride

117
Q

What is formed when an aldehyde is reacted with peroxyacids (or mcpba)?

A

Baeyer-Villiger reaction: carboxylic acid