Reactions of aldehydes and ketones:

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• Reactions of aldehydes and ketones
• oxidation
• reduction
• nucleophilic addition
• Aldehydes are easily oxidized, ketones are not.
• Aldehydes are more reactive in nucleophilic
  additions than ketones.

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alkane
alcohol
reduction
reduction
aldehyde ketone
addition product
nucleophilic addition
oxidation
carboxylic acid
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nucleophilic addition to carbonyl
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Mechanism nucleophilic addition to carbonyl
1)
2)
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Mechanism nucleophilic addition to carbonyl,
acid catalyzed
1) 2) 3)
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• Aldehydes ketones, reactions
• Oxidation
• Reduction
• Addition of cyanide
• Addition of derivatives of ammonia
• Addition of alcohols
• Cannizzaro reaction
• Addition of Grignard reagents
• 8) (Alpha-halogenation of ketones)
• 9) (Addition of carbanions)

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• 1) Oxidation
• Aldehydes (very easily oxidized!)
• CH3CH2CH2CHO KMnO4, etc. ?
  CH3CH2CH2COOH
• carboxylic acid
• CH3CH2CH2CHO Ag ? CH3CH2CH2COO-
  Ag
• Tollens test for easily oxidized compounds like
  aldehydes.
• (AgNO3, NH4OH(aq))

Silver mirror
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Ketones only oxidize under vigorous conditions
via the enol.
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b) Methyl ketones
Yellow ppt
test for methyl ketones
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• 2) Reduction
• To alcohols

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Then H ? alcohol
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Reduction b) To hydrocarbons
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3) Addition of cyanide
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1) 2)
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Cyanohydrins have two functional groups plus one
additional carbon. Nitriles can be hydrolyzed to
carboxylic acids in acid or base
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4) Addition of derivatives of ammonia
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1) 2) 3)
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melting points of derivatives ketones b
p semi- 2,4-dinitro- oxime
carbazone phenylhydrazone
2-nonanone 195 119 56 acetophenone 202
199 240 60 menthone 209 189
146 59 2-methylacetophenone 214 205
159 61 1-phenyl-2-propanone 216 200
156 70 propiophenone 220 174
191 54 3-methylacetophenone 220 198
207 55 isobutyrophenone 222 181 163 94
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5) Addition of alcohols
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• Cannizzaro reaction. (self oxidation/reduction)
• a reaction of aldehydes without a-hydrogens

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Formaldehyde is the most easily oxidized
aldehyde. When mixed with another aldehyde that
doesnt have any alpha-hydrogens and conc. NaOH,
all of the formaldehyde is oxidized and all of
the other aldehyde is reduced. Crossed Cannizzaro
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7) Addition of Grignard reagents.
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1) 2)
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3 synthesis of alcohols. Used to build larger
molecules from smaller organic compounds.
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• Aldehydes ketones, reactions
• Oxidation
• Reduction
• Addition of cyanide
• Addition of derivatives of ammonia
• Addition of alcohols
• Cannizzaro reaction
• Addition of Grignard reagents
• 8) (Alpha-halogenation of ketones)
• 9) (Addition of carbanions)

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• Planning a Grignard synthesis of an alcohol
• The alcohol carbon comes from the carbonyl
  compound.
• The new carbon-carbon bond is to the alcohol
  carbon.

New carbon-carbon bond
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The Grignard Song (sung to the tune of America
the Beautiful) Harry Wasserman The carbonyl
is polarized, the carbon end is plus. A
nucleophile will thus attack the carbon
nucleus. The Grignard yields an alcohol of
types there are but three. It makes a bond that
corresponds from C to shining C.
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or
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HX
Mg
ROH
RX
RMgX
larger alcohol
H2O
ox.
-CO
ROH
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Stockroom alcohols of four-carbons or
less (methanol, ethanol, 1-propanol, 2-propanol,
1-butanol, 2-butanol, 2-methyl-2-propanol,
2-methyl-1-propanol.) benzene cyclohexanol any
needed inorganic reagents or solvents.
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Grignard synthesis of 4-methyl-2-pentanol from
alcohols of four-carbons or less Step one
determine the carbonyl compound and Grignard
reagent that you would use
H2O
CH3 CH3CHCH2CHCH3 OH
CH3 CH3CHCH2MgBr CH3CHO
Step two show the syntheses of the Grignard
reagent and the carbonyl compound from alcohols
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CH3 HBr CH3
Mg CH3 CH3CHCH2OH
CH3CHCH2Br CH3CHCH2MgBr
H K2Cr2O7
CH3 CH3CH2OH
CH3CHO CH3CHCH2CHCH3
special cond.
OH
4-methyl-2-pentanol
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2-phenyl-2-propanol
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1-methylcyclohexanol
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cyclohexylmethanol
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aldehyde
RCOOH
ketone
ROH
ROR
alkene
RX
Alcohols are central to organic syntheses
alkyne
RH
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HX
Mg
ROH
RX
RMgX
larger alcohol
H2O
ox.
-CO
ROH
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Using the Grignard synthesis of alcohols we can
make any alcohol that we need from a few simple
alcohols. From those alcohols we can synthesize
alkanes, alkenes, alkynes, alkyl halides, ethers,
aldehydes, ketones, carboxylic acids eg.
Outline all steps in a possible laboratory
synthesis of 3-methyl-1-butene from alcohols
of four carbons or less.
CH3 CH3CHCHCH2
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Retrosynthesis alkenes, syntheses 1.
Dehydrohalogenation of an alkyl halide 2.
Dehydration of an alcohol 3. Dehalogenation of
a vicinal dihalide 4. Reduction of an
alkyne Methods 3 4 start with compounds that
are in turn made from alkenes.
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Dehydration of an alcohol? CH3
H CH3CHCHCH3 yields a mixture of
alkenes OH CH3
H CH3CHCH2CH2-OH yields a mixture of
alkenes E1 mechanism via carbocation!
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Dehydrohalogenation of an alkyl halide?
CH3 KOH(alc) CH3CHCHCH3
yields a mixture of alkenes Br
CH3 KOH(alc)
CH3 CH3CHCH2CH2-Br CH3CHCHCH2 only
product ?
E2 mechanism, no
carbocation, no rearrangement
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CH3 HBr
CH3 CH3CHCH2CH2-OH CH3CHCH2CH2-Br 1o
alcohol, SN2 mechanism, no rearrangement!
CH3 KOH(alc)
CH3 CH3CHCH2CH2-Br CH3CHCHCH2 Use the
Grignard synthesis to synthesize the intermediate
alcohol from the starting materials.
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CH3 PBr3 CH3
Mg CH3 CH3CHCH2-OH
CH3CHCH2Br
CH3CHCH2MgBr K2Cr2O7 CH3OH
H2CO
special cond. H2O

CH3


CH3CHCH2CH2-OH HBr
CH3 KOH(alco)
CH3 CH3CHCHCH2 CH3CHCH2CH2-Br