Chapter 17: Aldehydes and Ketones (The Carbonyl Group) Flashcards Preview

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Flashcards in Chapter 17: Aldehydes and Ketones (The Carbonyl Group) Deck (47)
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1
Q

Carbonyl Group

A

contains an oxygen atom and two lone parts that allow it to function as a weak Lewis base and has a highly polarized carbon-oxygen bond making the carbonyl group electrophilic
carbon and oxygen are sp2 hybridized and are on the same plane as the two additional groups with bond angles with carbon of 120°

2
Q

Oxidation of Alcohols

A

PCC, CH2Cl2

forms an aldehyde

3
Q

PCC, CH2Cl2

A

Oxidation of Alcohols to form Aldehydes

4
Q

Ozonolysis of Alkenes

A
  1. O3, CH2Cl2

2. (CH3)2S

5
Q
  1. O3, CH2Cl2

2. (CH3)2S

A

Ozonolysis of Alkenes to form Aldehydes or Ketones

6
Q

Hydration of Alkynes

A

H2O, H+, Hg2+

yields enols that tautomerize to carbonyls

7
Q

H2O, H+, Hg2+

A

Hydration of Alkynes to form Aldehydes or Ketones from Enols

8
Q

Friedel-Crafts Acylation

A

RCOCl, AlCl3

makes ketone substituent on benzene

9
Q

RCOCl, AlCl3

A

Friedel-Crafts Acylation

10
Q

Selective Alcohol Oxidation

A

CrO3, H2SO4, acetone, 0°C

11
Q

CrO3, H2SO4, acetone, 0°C

A

Selective Alcohol Oxidation

12
Q

Selective Oxidation of Allylic Alcohols

A

MnO3, CHCl3, 25°C

13
Q

MnO3, CHCl3, 25°C

A

Selective Oxidation of Allylic Alcohols

14
Q

NaBH4 or LiAlH4

A

hydride reagents, reduce carbonyls

15
Q

Reduction of Carbonyls

A

NaBH4 or LiAlH4

16
Q

Nucleophilic Addition-Protonation of Carbonyls

A

basic conditions, strong nucleophiles
nucleophile attacks carbonyl carbon, pushes e- from DB to oxygen to form alkoxide ion, addition of water, O attacks H in water to form OH

17
Q

Electrophilic Protonation-Addition

A

acidic conditions, weak or neutral nucleophile

e- on O attack H+, NuH attacks carbonyl C, e- pushed to O to eliminate + charge, H is abstracted from Nu group

18
Q

Carbonyl Hydrates

A

R2C(OH)2
formed when water attacks a carbonyl facilitated by acid or base
base catalyzed is nucleophilic addition-protonation
acid catalyzed is electrophilic protonation-addition

19
Q

Hydration of Carbonyls

A

OH is added to carbonyl C to form R2C(OH)2
reversible
EWG increase + charge at C and makes more reactive, ketone equilibrium lies to left and aldehyde equilibrium lies to the right

20
Q

Hemiacetals

A

OH
R-C-OR’
H
formed from aldehyde reversibly, formation is not favorable
if excess alcohol and H+ is present will form an acetal

21
Q

Hemiketals

A

OH
R-C-OR’
R
formed from ketone reversibly, formation is not favorable
if excess alcohol and H+ is present will form an ketal

22
Q

Acetals

A

OR’
R-C-OR’
H
can be isolated by neutralizing the acid catalyst
adding excess H2O will shift equilibrium to the left (acetal hydrolysis)

23
Q

Ketals

A

OR’
R-C-OR’
R

24
Q

Acetal Protecting Groups

A

formation is reversible

can be used to protect the carbonyl group using diols

25
Q

Diols

A

convert aldehydes and ketones to cyclic acetals which are more stable

26
Q

Cyclic Acetalization

A

aldehyde + diol (OHCH2CH2OH) =(H+)=> cyclic acetal + H2O

27
Q

Thiols

A

HSCH2CH2SH

react with carbonyl to form thioacetals using a Lewis Acid (BF3, ZnCl2)

28
Q

Thioacetals

A

sulfur analogs of cyclic acetals

29
Q

Thioacetal Formation

A

HSCH2CH2SH, ZnCl2, (CH3CH2)2O, 25°C

30
Q

HSCH2CH2SH, ZnCl2, (CH3CH2)2O, 25°C

A

Thioacetal Formation

31
Q

Thioacetal Hydrolysis

A

H2O, HgCl2, CaCO3, CH3CH

removes thiol group and restores aldehyde or ketone

32
Q

H2O, HgCl2, CaCO3, CH3CH

A

Thioacetal Hydrolysis

33
Q

Thioacetal Desulfurization

A

Raney Ni, H2

removes thiol group and replaces it with 2 H atoms

34
Q

Raney Ni, H2

A

Thioacetal Desulfurization

35
Q

Imines

A

RNC(R’)2
formed from hemiaminals by losing H2O and forming CN
can be isolated if water is removed by continuous distillation of the reaction mixture

36
Q

Hemiaminals

A

R H
N
R2-C-OH
formed from ketones or aldehydes by adding R-NH2

37
Q

Enamine

A

unsaturated compound derived by the condensation of an aldehyde or ketone with a secondary amine

38
Q

Deoxidation

A

reduction of the carbonyl group to CH2

can occur by Clemmensen reduction, thioacetal desulfurization or the Wolff-Kishner Reduction

39
Q

Hydrazones

A

R
R-C=N-NH2
formed by condensation of a hydrazine (H2N-NH2) with aldehyde/ketone

40
Q

H2N-NH2, CH3CH2OH

A

formation of a hydrazone

41
Q

Wolff-Kishner Reduction

A

hydrazone decomposes when treated with base at high temperatures
R
R-C=N-NH2 + NaOH =(HOCH2CH2)2O, 180-200°C=> RCH2R’ + N2

42
Q

Cyanohydrins

A

formed when hydrogen cyanide adds reversibly to a carbonyl
CN
Ph-OH
reagents: NaCN, conc. HCl

43
Q

NaCN, conc. HCl

A

formation of cyanohydrin from ketone/aldehyde

44
Q

Phosphorous Ylide

A

reagent in nucleophilic additions that contains a carbocation stabilized by an adjacent positively charged phosphorous group

45
Q

Wittig Reaction

A

phosphorous ylide attacks ketones/aldehydes to form C=C
produces mostly cis product
conjugation in the ylide produces trans products

46
Q

R=P(C6H5)3, THF

A

Witting Reaction Reagents

47
Q

Witting Reaction Reagents

A

R=P(C6H5)3, THF