Chapter 19- Aldehydes and Ketones

Question 1

What is the suffix for ketones?

Answer 1

-one

Question 2

What is the suffix for aldehydes?

Answer 2

-al

Question 3

What is the IR signal for a ketone?

Answer 3

~1715 cm -1

Question 4

What is the IR signal for an Aldehyde?

Answer 4

A weak 2700-2800 C-H stretch

Question 5

How do you turn a Primary ROH into an aldehyde?

Answer 5

PCC, CH2Cl2
or
DMP, CH2Cl2
or
1) DMSO (COCl2)
2) Et2

Question 6

How do you create an aldehyde from an RH=RH (alkene)?

Answer 6

Ozonolysis-
1) O3
2) DMS

Question 7

How do you create a ketone from an alkene?

Answer 7

Ozonolysis-
1) O3
2) DMS

Question 8

How do you create an aldehyde from an alkyne?

Answer 8

Hydroboration oxidation-

1) R2B-H
2)H202, NaOH

Question 9

How do you create a ketone from an alkyne?

Answer 9

Acid Hydration-

H2SO4, H2O
HgSO4

Question 10

Name this molecule

Answer 10

Formaldehyde

Question 11

Name this molecule

Answer 11

Acetaldehyde

Question 12

Name this molecule

Answer 12

Benzaldehyde

Question 13

How do you make a ketone from a secondary alcohol?

Answer 13

Oxidation reaction with

Na2Cr2O7
H2SO4, H2O

Question 14

How do you synthesize a ketone attached to a benzene ring from a benzene ring?

Answer 14

Friedel-Crafts acylation

Question 15

How do you synthesize an aldehyde attached to a benzene ring from a benzene ring?

Answer 15

Gattermann-Koch formylation
CO, HCl

AlCl3/CuCl

Question 16

Describe the carbon of the carbonyl within the aldehyde/ketone

Answer 16

-Electrophilic
-Has a delta plus from Induction
-Attacked by nucleophiles

Question 17

match the strength of the nucleophiles to the type to conditions and if it is reversible or not

Answer 17

Weak Nucleophile, Acid Conditions, Reversible

Strong nucleophile, base conditions, irreversible.

Question 18

What is more reactive? Aldehydes or Ketones?

why?

Answer 18

Aldehydes are more reactive:
1. Less sterically hindered
2. Only has one electron donating alkyl group, a delta plus on the carbonyl carbon

Question 19

How do you turn a ketone into a Secondary Alcohol? (Hydride strong nucleophile reagent)

Answer 19

1)LAH
2)H2O

or

NaBH4, MeOH

form enantiomers

Question 20

What is another way to make an alcohol from a ketone/aldehyde with a strong carbon nucleophile?

Answer 20

Grignard reagent

Question 21

How do you make a cyanohydrin from an aldehyde/ketone?

Answer 21

KCN, HCN

Question 22

In the presence of water, what is a ketone/aldehyde in equilibrium with?

Answer 22

Its hydrate

Question 23

How do you synthesize an acetal?

Answer 23

An aldehyde/ketone, 2 moles of ROH, acid catalyzed.

Question 24

What is an Acetal?

Answer 24

Tetrahedral carbon with two OR groups on it

Question 25

What are two acid catalysts used for acetal formation?

Answer 25

TsOH or Sulfuric Acid

Question 26

Are acetals favored at equilibrium for most aldehydes?

Answer 26

Yes

Question 27

Are acetals favored at equilibrium for most ketones?

Answer 27

No

Question 28

In acetal formation, under acidic conditions, what charge should the reaction species have?

Answer 28

A neutral or +1 formal charge

Question 29

In acetal formation, what is synthesized when a Diol is used

Answer 29

A cyclic acetal

Question 30

How can you control the reversibility of acetal formation

Answer 30

Add/Take away water remove water: favor acetal Add water: favor ketone/aldehyde

Question 31

What do you synthesize when an acetal undergoes hydrolysis?

Answer 31

An aldehyde/ketone

Question 32

Will an acetal react under base conditions?

Answer 32

No No reaction occurs

Question 33

What is a hemiacetal?

Answer 33

The intermediate formed in the conversion of a ketone/aldehyde to an acetal. These are hard to isolate, but cyclic hemiacetals can be isolated

Question 34

When is a cyclic hemiacetal possible?

Answer 34

When a compound contains both a carbonyl and a hydroxy group

Question 35

What is created when an aldehyde/ketone is reacted with two moles of thiol (RSH)?

Answer 35

A thioacetal Works the same way as alcohols, even the cyclic ones

Question 36

How can a thioacetal be converted to an alkane?

Answer 36

Raney nickel (RaNi)

Question 37

What is synthesized when an aldehyde/ketone reacts with a primary amine under acidic conditions?

Answer 37

an Imine C=N

Question 38

What does the pH have to be for the formation of an imine?

Answer 38

~4-5 Too low: all amines are pronated Too high: not enough acid to catalyze reaction

Question 39

What is the product?

Answer 39

Cyclohexanone imine + water

Question 40

What is the product?

Answer 40

Question 41

What is the product?

Answer 41

Question 42

What is synthesized when an aldehyde/ketone reacts with a secondary amine under acidic conditions?

Answer 42

An enamine

Question 43

What happens when an imine/enamine is reacted with water?

Answer 43

It undergoes hydrolysis and reverts back into an aldehyde/ketone

Question 44

Describe the steps of the Wolff-Kishner Reduction

Answer 44

It converts a ketone to an alkane Form hydrazone, then heat with strong base like KOH or potassium tert-butoxide. * Use a high-boiling solvent: ethylene glycol, diethylene glycol, or DMSO. * A molecule of nitrogen is lost in the last steps of the reaction

Question 45

What do you get when you react an aldehyde/ketone with a phosphorus ylide (RCPPh3)?

Answer 45

An alkene (Wittig reaction)

Question 46

How does one synthesize a Wittig reagent?

Answer 46

Start with an alkyl halide 1.PPh3 2. BuLi (CH3CH2CH2CH2 Li)

Question 47

What type of alkene is favored when the Wittig reagent is derived from a simple alkyl halide?

Answer 47

Z alkene (same side)

Question 48

What type of alkene is favored when the Wittig reagent contains an electron withdrawing group or a sterically bulky group?

Answer 48

E alkene (different sides)