Alpha Carbon Chemistry: Enols & Enolates new

Question 1

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

Answer 1

Enol

Question 2

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

Answer 2

Enolate

Question 3

Enols will undergo _____________ in either acid or base catalyzed

Answer 3

Tautomerization

Question 4

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

Answer 4

Enolate

Question 5

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

Answer 5

Negative charge carbon or negative charge oxygen

Question 6

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

Answer 6

Alpha

Question 7

A strong base or ______ is used to form an enolate

Answer 7

LDA

Question 8

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

Answer 8

Have both the enolate & ketone presence at equilibrium

Question 9

When treated with NaH or LDA the ketone will _______

Answer 9

Only form an enolate

Question 10

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

Answer 10

Alpha

Question 11

What is the mechanism for acid-catalzyed halogenation?

Answer 11

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

Question 12

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

Answer 12

The more substituated

Question 13

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

Answer 13

Undego elimination to form a double bond at the alpha position

Question 14

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

Answer 14

Undergo halogentation at the alpha position

Question 15

What is the Hell-Volhard- Zelinsky reaction?

Answer 15

The halogenation of a carboxylic acid at the alpha position

Question 16

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

Answer 16

Undergo halogenation at the alpha position

Question 17

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

Answer 17

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

Question 18

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

Answer 18

It occurs twice

Question 19

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

Answer 19

Wil form a carboxylic acid (Halofrom reaction)

Question 20

When an aldehyde is treated with NaOH & water it ___________

Answer 20

Forms an aldol addition reaction

Question 21

The product of an aldol addition reaction is always __________

Answer 21

A beta Hydroxy aldehyde or ketone

Question 22

What is the mechanism for an aldol addition reaction?

Answer 22

1. Proton transfer
2. Nucleophilic attack
3. Proton transfer

Question 23

In equilibirum with simple aldehydes the equilibirum favors ________

Answer 23

The adol product

Question 24

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

Answer 24

The ketone

Question 25

What is the mechanism for a retro adol reaction?

Answer 25

1. Proton transfer 2. Loss of leaving group 3. Proton trasnfer

Question 26

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

Answer 26

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

Question 27

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

Answer 27

Double bond between the alpha beta position

Question 28

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

Answer 28

An alpha beta-unsataurated aldehyde or ketone

Question 29

What is the mechanism for an adol condensation reaction?

Answer 29

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

Question 30

A crossed aldol reaction will occur if what?

Answer 30

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

Question 31

Crossaldehyde reaction can also be perform with what?

Answer 31

Benzaldehyde

Question 32

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

Answer 32

Two carbonyl groups

Question 33

Intramolecular reaction will favor what type of products?

Answer 33

5 or 6 meber rings

Question 34

What is a claisen condensation reaction?

Answer 34

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

Question 35

When doing a condensation reaction the starting ester must have \_\_\_\_\_\_\_

Answer 35

Two alpha protons

Question 36

When performing an claisen condensation reaction the base used must \_\_\_\_\_\_

Answer 36

Have the same group as the ester group

Question 37

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

Answer 37

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

Question 38

What is a Dieckmann reaction?

Answer 38

Claisen condensation reaction undergo intramolecularly formation

Question 39

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

Answer 39

1. Formation of an enolate 2. Treated with an alkyl halide

Question 40

When an unsymmetrical ketone is present alkylation will occur where?

Answer 40

At the more substituted position

Question 41

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

Answer 41

Alkylation at the least substituted position

Question 42

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

Answer 42

Occurs at the more substituated position

Question 43

What is the malonate ester synthesis?

Answer 43

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

Question 44

What is the reagen tused in malonate synthesis?

Answer 44

Diethyl malonate

Question 45

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

Answer 45

Carboxylic acid is formed

Question 46

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

Answer 46

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

Question 47

What is an acetoacetic ester synthesis?

Answer 47

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

Question 48

The alpha beta unsaturated aldehyde or ketone has _______ positions

Answer 48

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

Question 49

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

Answer 49

The carbon at the carbonyl group

Question 50

R₂CuLi like to attack the _____ position of the unsaturated compound

Answer 50

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

Question 51

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

Answer 51

Micheal donor, micheal acceptor

Question 52

Only a double stabilize enolate can be a \_\_\_\_\_\_\_

Answer 52

Micheal donor

Question 53

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

Answer 53

Enamine

Question 54

What is the process for a stork enamine reaction?

Answer 54

1. Formation os an enamine 2. Micheal addition 3. Hydrolysis

Question 55

What is an annulation reaction?

Answer 55

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