Aldehydes and Ketones
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Transcript of Aldehydes and Ketones
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Aldehydes and KetonesAldehydes and Ketones
Chapter 5Chapter 5
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Aldehydes and KetonesAldehydes and Ketones
Functional group is OFunctional group is O
The carbonyl l lThe carbonyl l l
group Cgroup C
Aldehyde = Carbonyl group is 1°Aldehyde = Carbonyl group is 1°
Ketone = Carbonyl group is 2°Ketone = Carbonyl group is 2°
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AldehydeAldehyde
RCHO ArCHORCHO ArCHO
BenzaldehydeBenzaldehyde
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KetonesKetones
RCORRCOR ArCOArArCOAr
ArCORArCOR
OO
C – C-C-CC – C-C-C
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Naming AldehydesNaming Aldehydes
Drop –e from alkane and add –alDrop –e from alkane and add –al
MethanalMethanal Propanal Propanal
2-chlorohexanal2-chlorohexanal
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PracticePractice
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Naming Ketones (2 ways)Naming Ketones (2 ways)
1.1. IUPAC - # chain from the end IUPAC - # chain from the end closest to the carbonyl, give the closest to the carbonyl, give the carbon #, drop –e add –onecarbon #, drop –e add –one
2.2. Name the groups on either side Name the groups on either side of the carbonyl and follow with of the carbonyl and follow with ketone ketone list groups by order of list groups by order of sixe of molar mass (smaller 1sixe of molar mass (smaller 1stst))
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PracticePractice
2-butanone2-butanone
methyl ethyl Ketonemethyl ethyl Ketone
3-hexanone3-hexanone
ethyl propyl ketoneethyl propyl ketone
Draw 2 – pentanone and name it the 2Draw 2 – pentanone and name it the 2ndnd way way
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PracticePractice
For the “old” way to name a ketone to use a For the “old” way to name a ketone to use a phenyl, the ring must be bonded directly to phenyl, the ring must be bonded directly to the carbonylthe carbonyl
3-phenyl-3-propanone3-phenyl-3-propanone
ethyl phenyl ketoneethyl phenyl ketone
4-phenyl – 3 – butanone/no secondary name4-phenyl – 3 – butanone/no secondary name
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PracticePractice
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Preparation of AldehydesPreparation of Aldehydes
1.1. Oxidation of 1° Alcohols (lose HOxidation of 1° Alcohols (lose H22))
RCHRCH22OH OH PCC PCC CH2Cl2CH2Cl2 RCHO + H RCHO + H22
Catalysts are Catalysts are
PCC = Pyridinium chororchrmate,PCC = Pyridinium chororchrmate, C C55HH66NCrONCrO33ClCl
Dichloromethane = CHDichloromethane = CH22ClCl22
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PracticePractice
Form Propanal by oxidationForm Propanal by oxidation
CHCH33CHCH22CHCH22OH OH CH CH33CHCH22CHO + HCHO + H22
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Practice Practice
2. Oxidize 1-hexanol O2. Oxidize 1-hexanol O
C-C-C-C-C-C-OH C-C-C-C-C-C-OH (Catalyst)(Catalyst) C-C-C-C-C-C-H C-C-C-C-C-C-H
+ H+ H22
CHCH33(CH(CH22))44CHCH22OHOH (Catalyst)(Catalyst) CH CH33(CH(CH22))44CHOCHO
+ H+ H22
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Practice Practice
Synthesize propanal (str)Synthesize propanal (str)
C-C-C + ClC-C-C + Cl2 2 C-C-C-Cl + HCl C-C-C-Cl + HCl
C-C-C-Cl + HC-C-C-Cl + H22O O C-C-C-OH + HCl C-C-C-OH + HCl
C-C-C-OH C-C-C-OH (Catalyst)(Catalyst) C-C-C=O + H C-C-C=O + H22
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The 2The 2ndnd Reaction Type Reaction Type
2. Reduction of acid chlorides (add H2. Reduction of acid chlorides (add H22))
+ H+ H22 (Pt/Pd)(Pt/Pd) + HCl + HCl
RCOCl + HRCOCl + H22 (Pt/Pd)(Pt/Pd) RCHO + HCl RCHO + HCl
**Acid chlorides look like aldehydes, but Acid chlorides look like aldehydes, but have a –Cl where the end –H is. (We have a –Cl where the end –H is. (We will look at them more closely later)will look at them more closely later)
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PracticePractice
Form propanal by reductionForm propanal by reduction
CHCH33CHCH22COCl + HCOCl + H22 (Pt/Pd)(Pt/Pd) CH CH33CHCH22CHO + HClCHO + HCl
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Synthesis of BenzaldehydeSynthesis of Benzaldehyde
The =O is not directly on the The =O is not directly on the benzene, so you can’t follow he benzene, so you can’t follow he steps for an alcohol – you have to steps for an alcohol – you have to use the following…use the following…
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Synthesis of BenzaldehydeSynthesis of Benzaldehyde
+ -AlCl+ -AlCl33 + HCl + HCl
+ 2Cl+ 2Cl22 + 2HCl + 2HCl
+ H+ H22O O + 2HCl + 2HCl
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Preparation of KetonesPreparation of Ketones
1. Oxidation of 2° alcohols1. Oxidation of 2° alcohols
OH OOH O
R-C-R’ R-C-R’ (Catlaysts)(Catlaysts) R-C-R’ + H R-C-R’ + H22
RCHOHR’ RCHOHR’ (Catlaysts)(Catlaysts) RCOR’ + H RCOR’ + H22
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Practice Practice
Oxidize 2-pentanol (str, cond, name product)Oxidize 2-pentanol (str, cond, name product)
OH OOH O
C-C-C-C-C C-C-C-C-C (Catalyst)(Catalyst) C-C-C-C-C + H C-C-C-C-C + H22
2-pentanone/methyl propyl ketone2-pentanone/methyl propyl ketone
CHCH33CHOH(CHCHOH(CH22))22CHCH33 (Ctlyst) (Ctlyst) CHCH33CO(CHCO(CH22)2CH)2CH33
+ H+ H22
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PracticePractice
Form methyl ethyl ketone (str, cond, name Form methyl ethyl ketone (str, cond, name reactant)reactant)
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PracticePracticeSynthesize 3-heptanone (cond.)Synthesize 3-heptanone (cond.)CHCH33(CH(CH22))55CHCH33+Cl+Cl22CHCH33CHCH22CHCl(CHCHCl(CH22))33CHCH33 + +
HClHCl
CHCH33CHCH22CHCl(CHCHCl(CH22))33CHCH33 + H + H22O O
CHCH33CHCH22CHOH(CHCHOH(CH22))33CHCH33 + HCl + HCl
CHCH33CHCH22CHOH(CHCHOH(CH22))33CHCH3 3 (Cats)(Cats)
CHCH33CHCH22CO(CHCO(CH22))33CHCH33 + H + H22
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The 2The 2ndnd Reaction Type Reaction Type
2. Friedel – Crafts Acylation - acyl group2. Friedel – Crafts Acylation - acyl group
RCORCO
O OO O
ArH + R-C-Cl –AlClArH + R-C-Cl –AlCl33 R-C-Ar + HCl R-C-Ar + HCl
ArH + RCOCl –AlClArH + RCOCl –AlCl33 RCOAr + HCl RCOAr + HCl
Benzene must bond directly to the C=OBenzene must bond directly to the C=O
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PracticePractice
Form ethyl phenyl ketone (str, cond)Form ethyl phenyl ketone (str, cond)
C-C-C-Cl + -AlClC-C-C-Cl + -AlCl33 C-C-C- + HCl C-C-C- + HCl
CHCH33CHCH22COCl + CCOCl + C66HH66 –AlCl –AlCl33 CH CH33CHCH22COCCOC66HH55 + +
HClHCl
Form pentyl phenyl ketone (str, cond)Form pentyl phenyl ketone (str, cond)
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Rxns of Aldehydes and KetonesRxns of Aldehydes and Ketones
1.1. Reduction of aldes and kets to alcoholsReduction of aldes and kets to alcohols
OO
R-C-H + HR-C-H + H2 2 –Pt/Pd–Pt/Pd R-C-OH R-C-OH
RCHO + HRCHO + H22 –Pt/Pd –Pt/Pd RCH RCH22OHOH
O OO O
R-C-R + HR-C-R + H2 2 –Pt/Pd–Pt/Pd R-C-R R-C-R
RCOR + HRCOR + H22 –Pt/Pd –Pt/Pd RCHOHR RCHOHR
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PracticePractice
Reduce 2-hexanone (str,cond, name prod)Reduce 2-hexanone (str,cond, name prod)
O OHO OH
C-C-C-C-C-C + HC-C-C-C-C-C + H22 –Pt/Pd –Pt/Pd C-C-C-C-C-C C-C-C-C-C-C
2-hexanone2-hexanone
CHCH33CO(CHCO(CH22))33CHCH33 + H + H22 –Pt/Pd–Pt/Pd CHCH33CHOH(CHCHOH(CH22))33CHCH33
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PracticePractice
Reduce Pentanal (str,cond, name prod)Reduce Pentanal (str,cond, name prod)
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The 2The 2ndnd Reaction Type Reaction Type
2. Oxidation of aldehydes to carboxylic acids2. Oxidation of aldehydes to carboxylic acids
OO
*Carboxyl group: COOH -C-OH*Carboxyl group: COOH -C-OH
O OO O
R-C-H –KMnOR-C-H –KMnO44 R-C-OH R-C-OH
RCHO –KMnORCHO –KMnO44 RCOOH RCOOH
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ExamplesExamples
Oxidize ethanolOxidize ethanol
O OO O
C-C-H –KMnOC-C-H –KMnO44 C-C-OH ethanoic acid C-C-OH ethanoic acid
CHCH33CHO –KMnOCHO –KMnO44 CH CH33COCO22HH
*To name a carboxylic acid (must be on the *To name a carboxylic acid (must be on the 11stst C), drop –e from alkane and add –oic C), drop –e from alkane and add –oic acidacid
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ExamplesExamples
Synthanize pentanoic acid (cond)Synthanize pentanoic acid (cond)
CHCH33(CH(CH22))33CHCH33 + Cl + Cl2 2 CH CH33(CH(CH22))33CHCH22Cl + HClCl + HCl
CHCH33(CH(CH22))33CHCH22Cl Cl + + HH22OO CH CH33(CH(CH22))33CHCH22OH + OH + HClHCl
CHCH33(CH(CH22))33CHCH22OHOH–PCC/CH–PCC/CH22ClCl22CHCH33(CH(CH22))33CHO CHO + H+ H22
CHCH33(CH(CH22))33CHO –KMnOCHO –KMnO44 CH CH33(CH(CH22))33COCO22HH
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33RDRD Reaction Type Reaction Type
Rxn with alcohols to form hemiacetals and Rxn with alcohols to form hemiacetals and acetalsacetals
*Works well with aldehydes but difficule with *Works well with aldehydes but difficule with ketonesketones
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Example with KetoneExample with Ketone O O H+H+ OH OH H+ H+ OR’OR’
R-C-R + R’OH R-C-R + R’OH R-C-R + R’OH R-C-R + R’OH R-C-R R-C-R +H+H22OO
OR’ OR’OR’ OR’
hemiacetal acetalhemiacetal acetalRCOR + R’OH RCOR + R’OH –H+–H+ RCOR’(OH) + R’OH RCOR’(OH) + R’OH –H+–H+
RC(OR’)RC(OR’)22R + R +
HH22OO
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Example with AldehydeExample with Aldehyde
O O H+H+ OH OH H+ H+ OR’OR’
R-C-H + R’OH R-C-H + R’OH R-C-H + R’OH R-C-H + R’OH R-C-H R-C-H +H+H22OO
OR’ OR’OR’ OR’
RCHO + R’OH RCHO + R’OH –H+–H+ RCHOR’(OH) + R’OH RCHOR’(OH) + R’OH –H+–H+
RCH(OR’)RCH(OR’)22 + H + H22OO
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Practice ExamplePractice Example
React butanal w/ propanol (str, cond)React butanal w/ propanol (str, cond)
O OH OH OHO OH OH OH
C-C-C-C-H + C-C-CC-C-C-C-H + C-C-C –H+–H+ C-C-C-C-H + C-C-CC-C-C-C-H + C-C-C
O-C-C-CO-C-C-C
O-C-C-CO-C-C-C
-H+-H+ C-C-C-C-H + HC-C-C-C-H + H22
O-C-C-CO-C-C-C
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Practice ExamplePractice Example
Condensed version of the previous Condensed version of the previous exampleexample
CHCH33(CH(CH22))22CHO + CHCHO + CH33CHCH22CHCH22OH –H+OH –H+
CHCH33(CH(CH22))22CH(O(CHCH(O(CH22))22CHCH33)(OH) + )(OH) +
CHCH33CHCH22CHCH22OH –H+OH –H+
CHCH33(CH(CH22))22CH(O(CHCH(O(CH22))22CHCH33))22 + H + H22
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PracticePractice
React 2-pentanone with ethanol (str, cond) React 2-pentanone with ethanol (str, cond)