Deck 22: Condensations and Alpha Substitutions of Carboxyl Compounds

Question 1

For the equilibrium shown below, is the K_eq greater or less than 1?

Answer 1

greater than 1

Question 2

The relationship between ketones and their corresponding enols is one of ________.

A) allotropes
B) tautomers
C) enantiomers
D) diastereomers
E) cis-trans isomers

Answer 2

tautomers

Question 3

Which of the pairs shown below are tautomers?

A)
B)
C)
D)

Answer 3

Question 4

Provide the structure of the more stable enol tautomer of 1-phenyl-2-octanone.

Question 5

Provide a detailed, stepwise mechanism for the acid-catalyzed enolization of acetaldehyde.

Question 6

Provide a detailed, stepwise mechanism for the base-catalyzed enolization of acetaldehyde.

Question 7

Which of the following compounds will not undergo reaction with an enolate?

A) 1-pentene
B) bromine
C) propanal
D) 1-bromobutane
E) benzoyl chloride

Question 8

Consider the reaction shown below. Use pKa values to determine which way the equilibrium lies.

Question 9

What type of reaction is shown below?

A) Aldol condensation
B) Claisen Condensation
C) Michael Addition
D) Alkylation

Question 10

Provide the structure of lithium diisopropylamide.

Question 11

Draw the important resonance forms for the enolate ion/s that are formed when acetophenone reacts with base.

Question 12

Disregarding stereoisomers, how many different enols can the β-diketone CH₃COCH₂COCH₂CH₃ form?

A) 0
B) 1
C) 2
D) 3
E) 4

Question 13

Provide the major organic product of the following reaction.

Question 14

Provide the structure of the enol of 2,2,4-trimethyl-3-pentanone.

Question 15

Which of the following reagents will quantitatively convert an enolizable ketone to its enolate salt?

A) lithium hydroxide
B) lithium diisopropylamide
C) methyllithium
D) diethylamine
E) pyridine

Question 16

The reaction of LDA with acetophenone produces ________.

A) an enol
B) an enolate
C) an ylide
D) alkylation
E) halogenation

Question 17

When 2-methylcyclohexanone is treated with catalytic base in excess D₂O, how many deuterium atoms become incorporated in the organic compound?

A) 0
B) 1
C) 2
D) 3
E) 5

Question 18

Show how an enolate can add to a carbonyl.

Question 19

Consider the reaction shown below. Use pKa values to determine which way the equilibrium lies.

Question 20

Disregarding stereoisomers, how many different enols can phenylacetone form?

A) 0
B) 1
C) 2
D) 3
E) 4

Question 21

Provide the major organic product of the following reaction.

Question 22

What iminium salt is produced in the reaction shown below?

Question 23

What alkyl halide would you add to perform the following alkylation reaction?

Question 24

What type of product results when 3-pentanone reacts with dimethylamine?

A) enolate
B) enol
C) amide
D) imine
E) enamine

Question 25

(S)-2-Methylbutanal ________ upon sitting in an acidic or a basic aqueous solution.

A) racemizes
B) esterifies
C) inverts completely to the R configuration
D) hydrolyzes
E) irreversibly forms the hydrate

Question 26

Predict the major organic product of the following reaction:

Question 27

When a ketone and its enol are in equilibrium, under most conditions the concentration of the enol is ________ the concentration of the ketone.

A) slightly higher than
B) equal to
C) much higher than
D) much lower than
E) exactly half of

Question 28

Which of the following ketones will give a positive iodoform test?

A) 4-heptanone
B) 3-hexanone
C) 2-hexanone
D) cyclohexanone
E) 2-methyl-3-pentanone

Question 29

What compound is produced in the reaction of cyclopentanone with Br₂ in acetic acid?

Question 30

Which of the following will alkylate a lithium enolate most rapidly?

A) methyl bromide
B) isopropyl bromide
C) neopentyl bromide
D) bromobenzene
E) 2-methylbromobenzene

Question 31

The α-halogenation of cyclohexanone ________.

A) is catalyzed by base
B) is slowed by the presence of acid
C) requires one equivalent of base
D) requires one equivalent of acid
E) is catalyzed by the sodium halide salt

Question 32

What is the carbon nucleophile which attacks molecular bromine in the acid-catalyzed α-bromination of a ketone?

A) an enolate
B) a Grignard reagent
C) an acetylide
D) a carbocation
E) an enol

Question 33

Provide the major organic product of the following reaction.

Question 34

Which of the following will react most slowly with an enamine?

A) isopropyl chloride
B) methyl bromide
C) acetyl chloride
D) benzyl chloride
E) allyl bromide

Question 35

When aldehydes are subjected to the same conditions that α-halogenate ketones (i.e., X₂ and aqueous acid or base), they are ________.

A) α-halogenated as well
B) reduced to alcohols
C) converted to the acid halide
D) oxidized to the acid or carboxylate
E) esterified

Question 36

What are the two key resonance structures for an enamine? Label the major and minor contributors.

Question 37

Provide the major organic product of the reaction shown below.

Question 38

In the iodoform reaction, a methyl ketone is converted to the ________ upon treatment with excess iodine and hydroxide.

A) carboxylate
B) acyl iodide
C) primary alkyl iodide
D) aldehyde
E) primary amide

Question 39

Provide the major organic product of the following reaction.

Question 40

Provide the major organic product of the reaction shown below.

Question 41

Provide the structure of the major organic product which results when PhCH₂CHO is treated with NaOH.

Question 42

Provide the structure of the aldol product that results when 5-methylhexanal is treated with hydroxide.

Question 43

Show how the following compound can be synthesized using an Aldol Condensation reaction.

Question 44

What reagents are needed to complete the following synthesis?

A) 1) NaOH / heat, 2) HCl (aq)
B) 1) NaOH / I₂, 2) HCl (aq)
C) 1) warm conc. KMnO₄ / NaOH, 2) HCl (aq)
D) 1) Ag(NH₃)₂OH, 2) HCl (aq)

Question 45

Which of the following is another name for the product of an aldol condensation?

A) β-hydroxyaldehyde
B) α-hydroxyaldehyde
C) acetal
D) β-ketoester
E) 1,3-dialdehyde

Question 46

Provide the major organic product of the following reaction.

Question 47

Predict the major organic product of the following reaction:

Question 48

Complete the following short synthesis by providing the necessary sequence of reagents.

Question 49

Provide a mechanism for the following reaction:
butanoic acid + Br₂ + PBr₃ → 2-bromobutanoyl bromide

Question 50

Provide a detailed, stepwise mechanism for the formation of acetate and bromodiiodomethane from bromoacetone, hydroxide and iodine.

Question 51

Complete the following reaction by filling in the necessary reagents.

Question 52

Why is the acid-catalyzed halogenation of ketones generally preferred over the base-promoted halogenation?

Question 53

Provide the major organic product of the following reaction.

Question 54

The following compound was found to inhibit HIV-1 (J. Med. Chem. 2011, 1812). Predict the structure of the hydrolysis product.

A)
B)
C)
D)

Question 55

The aldol condensation is ________.

A) an irreversible reaction
B) an equilibrium reaction
C) a tautomerization
D) an isomerization
E) a type of esterification

Question 56

An enolate attacks an aldehyde and the resulting product is subsequently protonated. What type of reaction is this?

A) a Fischer esterification
B) an acid-catalyzed aldol condensation
C) a base-mediated aldol condensation
D) a Hell-Volhard-Zelinsky reaction
E) a Selman-Jones reaction

Question 57

What organic compounds are produced when 2-pentanone undergoes the haloform reaction upon treatment with HO^- and excess Br₂?

Question 58

The Hell-Volhard-Zelinsky reaction involves ________.

A) the α-bromination of carboxylic acids
B) the α-bromination of ketones
C) the bromination of alcohols
D) the oxidation of aldehydes to acids
E) none of the above

Question 59

Provide the major organic product of the following reaction.

Question 60

Which set of reagents would best accomplish the following transformation?

A) Br₂ / HBr
B) Br₂ / PBr₃
C) Br₂ / NaOH
D) PBr₃

Question 61

What product results when pentanal is heated with sodium hydroxide?

Question 62

Provide the major organic product of the following reaction.

Question 63

Draw a mechanism and provide the structure of the aldol product that results when 4-methylpentanal is heated with sodium hydroxide.

Question 64

What product results when an aldol is dehydrated?

A) conjugated alkyne
B) β-diketone
C) β-ketoester
D) α,β-unsaturated aldehyde
E) β,γ-unsaturated aldehyde

Question 65

Provide the structure of the intramolecular aldol condensation/dehydration product that results when 2,6-heptanedione is heated in base.

Question 66

In theory a poorly planned crossed aldol reaction can produce how many different products?

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

Question 67

Which of the following could result from the dehydration of a self-aldol condensation product?

A) 4-methyl-3-penten-2-one
B) 4-methyl-4-penten-2-one
C) 4-methyl-5-hexen-2-one
D) 4-methyl-4-hexen-2-one
E) 3-methyl-4-penten-2-one

Question 68

Predict the outcome of the following reaction.

Question 69

Provide the structure of the ester that would undergo self-condensation to yield the
shown below.

Question 70

What two molecules were condensed in an aldol reaction to produce

Question 71

What two organic starting materials are required to produce cinnamaldehyde
via a crossed aldol condensation followed by dehydration?

Question 72

Provide the structure of the Claisen product in the self condensation of methyl phenylacetate.

Question 73

What two molecules were condensed in an aldol reaction to produce

Question 74

The following compound isolated from a marine sponge has been found to have anti-tubercular activity (Tet. Lett. 2007, 8851). Show how it may be constructed by an aldol reaction by drawing a structure of the starting material.

Question 75

What crossed-aldol product results when propanal is heated in the presence of excess 2,2-dimethylpropanal and sodium hydroxide?

Question 76

Name the aldol produced when butanal is treated with NaOH.

Question 77

Provide the structure of the product which results from the base-catalyzed condensation followed by dehydration between benzophenone and propanal.

Question 78

Predict the pK_a unit of the indicated proton within +/- 1 pK_a unit.

A) 5
B) 11
C) 19
D) 24

Question 79

Provide the sequence of steps necessary to synthesize the compound shown below from cyclohexene.

Question 80

What crossed-aldol product results when butanal is heated in the presence of excess benzaldehyde and sodium hydroxide?