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Organic Chemistry > Alpha Carbon Chemistry: Enols & Enolates new > Flashcards

Alpha Carbon Chemistry: Enols & Enolates new Flashcards

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1
Q

When a ketone is treated with catalytic acid or base it can form ______________ in equilibrium

A

Enol

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2
Q

When a ketone is treated with catatylic base it will form an __________ in equilibrium

A

Enolate

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3
Q

Enols will undergo _____________ in either acid or base catalyzed

A

Tautomerization

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4
Q

When treated with a strong base the alpha position of a ketone is deprotonated to form an __________

A

Enolate

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5
Q

Enolates are ambient nucleophiles because they can be attack from the _______ or _______

A

Negative charge carbon or negative charge oxygen

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6
Q

The ________ protons are usually the most acidic protons, so deprotonated the alpha protons

A

Alpha

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7
Q

A strong base or ______ is used to form an enolate

A

LDA

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8
Q

When treated with a strong base like NaOH or NaOEt a ketone will ________

A

Have both the enolate & ketone presence at equilibrium

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9
Q

When treated with NaH or LDA the ketone will _______

A

Only form an enolate

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10
Q

Under acid-catalyzed condition a ketone or aldehyde will undergo halogenation at the _______ position

A

Alpha

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11
Q

What is the mechanism for acid-catalzyed halogenation?

A
  1. Acid-catalyzed enol formation (Proton transfer twice)
  2. Nucleophilic attack
  3. Proton transfer
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12
Q

With an unsymmetrical ketone the halogenation reaction will occur at the _________ position

A

The more substituated

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13
Q

When treated with a base like pyridine or Li2CO3 the halogenated ketone will __________

A

Undego elimination to form a double bond at the alpha position

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14
Q

When carboxylic acid are treated with PBr3 and a halogen it will __________

A

Undergo halogentation at the alpha position

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15
Q

What is the Hell-Volhard- Zelinsky reaction?

A

The halogenation of a carboxylic acid at the alpha position

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16
Q

When a ketone is treated with NaOH & a halogen like Br2 then it will ___________

A

Undergo halogenation at the alpha position

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17
Q

What is the mechanism for a base halogenation of a ketone?

A
  1. Deprotonated the alpha proton (proton transfer)
  2. Nucleophilic attack
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18
Q

When more than one alpha proton is present in a base halogenation what happens?

A

It occurs twice

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19
Q

When a methyl ketone is treated with NaOH,Br2 & H3O+ what will happen?

A

Wil form a carboxylic acid (Halofrom reaction)

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20
Q

When an aldehyde is treated with NaOH & water it ___________

A

Forms an aldol addition reaction

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21
Q

The product of an aldol addition reaction is always __________

A

A beta Hydroxy aldehyde or ketone

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22
Q

What is the mechanism for an aldol addition reaction?

A
  1. Proton transfer
  2. Nucleophilic attack
  3. Proton transfer
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23
Q

In equilibirum with simple aldehydes the equilibirum favors ________

A

The adol product

24
Q

In equilibirum with the ketone the and adol product the equilibirum favors _________

A

The ketone

25
Q

What is the mechanism for a retro adol reaction?

A
  1. Proton transfer
  2. Loss of leaving group
  3. Proton trasnfer
26
Q

When heated in acidic or basic conditions the product of an aldol addition reaction will undergo elimination to produce ________

A

A double bond between the alpha & beta position with water as the bi products

27
Q

In basic condition when the adol product is treated with NaOH & heat it will form the _______

A

Double bond between the alpha beta position

28
Q

The product of an aldol condensation reaction (when an adol product is treated with acidic or basic condition & heat) what is always the product?

A

An alpha beta-unsataurated aldehyde or ketone

29
Q

What is the mechanism for an adol condensation reaction?

A
  1. Formation of the d=adol product through adol addition
  2. Elimination of water to form the double bond
30
Q

A crossed aldol reaction will occur if what?

A
  1. If one of the aldehydes lacks an alpha proton & has an unhindered carbonyl group (ex. formaldehyde)
  2. Cross aldol reaction can be used with LDA as a base
31
Q

Crossaldehyde reaction can also be perform with what?

A

Benzaldehyde

32
Q

Compounds that have ________ will undergo intramolecular aldol addition when treated with NaOH & heat

A

Two carbonyl groups

33
Q

Intramolecular reaction will favor what type of products?

A

5 or 6 meber rings

34
Q

What is a claisen condensation reaction?

A

A reaction where ester undergo condensation to form a beto-keto ester (like an adol addition reaction)

35
Q

When doing a condensation reaction the starting ester must have _______

A

Two alpha protons

36
Q

When performing an claisen condensation reaction the base used must ______

A

Have the same group as the ester group

37
Q

Cross claisen reaction will occur if what two criteria are met?

A
  1. If one ester has no alpha proton & can’t form an enolate
  2. A direct claisen condensation can be used with LDA
38
Q

What is a Dieckmann reaction?

A

Claisen condensation reaction undergo intramolecularly formation

39
Q

The alpha position of a ketone can be alkylated by what two steps?

A
  1. Formation of an enolate
  2. Treated with an alkyl halide
40
Q

When an unsymmetrical ketone is present alkylation will occur where?

A

At the more substituted position

41
Q

When a ketone is treated with LDA at lower temp what happens in an alkylation reaction?

A

Alkylation at the least substituted position

42
Q

When treated with LDA at higher temps what happens in an alkylation reaction?

A

Occurs at the more substituated position

43
Q

What is the malonate ester synthesis?

A

A techniques that uses malonate ester as the starting material & treats it with an alkyl halide to introduce two new carbons

44
Q

What is the reagen tused in malonate synthesis?

A

Diethyl malonate

45
Q

When diethyl malonate is alkylated & then treated with H3O+ what happens?

A

Carboxylic acid is formed

46
Q

When the malonate is turned into a carboxylic & treated with heat what happens?

A

An enol is formed & undergoes tautomerization with CO2 as the biproduct

47
Q

What is an acetoacetic ester synthesis?

A

Same as diethyl malonate but instead uses ethyl acetoacetate as the reagent

48
Q

The alpha beta unsaturated aldehyde or ketone has _______ positions

A

Two electrophilic position can attack the beta positon os the double bond or the carbon at the carbonyl group

49
Q

Grinard reagent like to attack _____ Positon in a micheal reaction?

A

The carbon at the carbonyl group

50
Q

R2CuLi like to attack the _____ position of the unsaturated compound

A

The beta position which then forms an enolate then treated with H3O+ to form an enol which then undergoes tautomerization to form the double bond oxyden

51
Q

In a micheal reaction the double stabilized enolate is the ______ & the alpha beta unsaturated compound is the ________

A

Micheal donor, micheal acceptor

52
Q

Only a double stabilize enolate can be a _______

A

Micheal donor

53
Q

For a regular ketone it will have to be treated with R2NH to form an ________ to undergo a micheal reaction

A

Enamine

54
Q

What is the process for a stork enamine reaction?

A
  1. Formation os an enamine
  2. Micheal addition
  3. Hydrolysis
55
Q

What is an annulation reaction?

A

A two step process to form a ring where a compound undergoes micheal reaction then intramolecular aldol condesation reaction

Organic Chemistry (47 decks)

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