Download Aldehydes/Ketones Solutions

ALDEHYDES/KETONES SOLUTIONS
Don’t forget the generic functional group structures and the common alkyl groups (s-butyl, etc.)
1. Draw structures of the following compounds
a) isovaleraldehyde
i)
2-bromocyclobutanecarbaldehyde
O
O
H
H
Br
b) -cyclobutylbutyraldehyde
j)
3-chlorobutanal
O
H
H
O
c) p-formylbenzaldehyde
O
O
C
C
H
H
d) -chloropropyl isobutyl ketone
Cl
k) 2,4-hexanedione
O
l)
O
3-oxobutanal
H
Cl
O
O
O
m) 1,3-cylcohexanedione
e) acetophenone
O
O
O
n) m-ethylbenzaldehyde
f) caproaldehyde
H
O
CH3CH2
O
g) -hydroxybutanal
H
o) 2-phenylpropanal
H
HO
H
O
h) sec-butyl isobutyl ketone
O
p) benzophenone
O
O
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ALDEHYDES/KETONES SOLUTIONS
2. Give the IUPAC name and, where possible, the common name for the following:
a)
f)
O
CH2
CH
CH2
C
C
H
(I) 1-cyclopentyl-3-buten-1-one
(c) allyl cyclopentyl ketone
3-oxocyclopentanecarbaldehyde
H3C
g)
O
b)
O
O
CH3
C
H
C
C
CH2
O
O
2,4-pentanedione
O
3-oxocycloheptanecarbaldehyde
O
h)
c)
Br
O
CH3CHCH C
CH(CH3)2
5-isopropyl-2-methyl-2-cyclohexen-1-one
F
5-bromo-4-fluoro-2-methyl-3-hexanone
O
i)
d)
CH3O
O
C H
m-methoxybenzaldehyde
2-cyclobuten-1-one
j)
e)
F
O
O
O
CH3CCH2CCH2CH3
1-fluoro-3-phenylpropanone
2,4-hexanedione
3. Draw the full mechanism (using arrows) and write the product of the base catalyzed
hydration of formaldehyde to a gem diol.
..
: O:
: O:
C
H
H
.. : OH
..
H
C
H
:O :
H
H
..
O
..
H
: O:
H
.. : OH
..
C
H
H
OH
Remember that only hydroxide and water are present in base catalysis
Note that catalysts are always regenerated.
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ALDEHYDES/KETONES SOLUTIONS
4. Draw structures and name the products of the following reactions
a)
O
H
N
+
CH3CH2CH
H2O
N
H
CH3CH2C
H
NO2
H
N
NH
NO2
propionaldehyde p-nitrophenylhydrazone
propionaldehyde
p-nitrophenylhydrazine
b)
H
O
H
C
+
H
H2O
N
H
OH
H
hydroxylamine
formaldehyde
OH
N
C
H
formaldoxime
5. Write the products of the following reactions. No mechanisms required
a)
O
CH2
N2H4, KOH
C
b)
O
CH2
CH2
H
NH(CH3)2, H3O+
C
CH3
CH
C
N(CH3)2
H
H
c)
1.
2.
O
CH2
C
MgBr
OH
H3O+
CH2
H
C
H
OH
1. LiAlH4
2. H2O
d)
CH2
C
OH
KCN, HCN
O
CH2
C
H
C
N
CH2
C
H
NH2
CH2
OH
H
H3O+

CH2
C
O
C
H
OH
PAGE 3
ALDEHYDES/KETONES SOLUTIONS
e)
O
CH2
C
OH
H3O+
CH2
H
C
H
OH
f)
H3C
CH3
O
C
C
Tollens reagent
Ag(NH3)2+
CH3
g)
H3C
NO Reaction. Tollen's reagent is very mild.
It only oxidizes aldehydes (to carboxylic acid salts)
CH3
O
C
C
O
CH3
HOCH2CH2OH, H3O+
H3C
C
h)
CH3
O
C
C
1. LiAlH4
2. H3O+
H3C
CH3
i)
CH
CH
C
CH3
OH
C
C
CH3
H
1. 1 equiv.
(CH3CH2)2CuLi
O
CH3
C
CH3
CH3
H3C
O
CH3
CH3
2. H O+
3
CH
H
O
CH
C
CH3
CH2CH3
This is a 1,4-addition to a conjugated enone.
PAGE 4
ALDEHYDES/KETONES SOLUTIONS
6. Write equations showing how the following transformations can be carried out. No
mechanisms required but show all reagents and intermediate products formed. More than
one step may be necessary
a)
O
O
C
H
C
H
H
mild oxidation of
1° alcohols stop at
aldehydes
CrO3 in N
MgBr
1
2
or
PCC in CH2Cl2
1°
H3O+
b)
CH2OH
O
O
C
O
HO
H
C
1 mole HOCH2CH2OH can be
used in place of 2 moles CH3OH
2 CH3OH
H3O+
OCH3
O
C
H3O+
OCH3
H
O
1 NaBH4
H
C
H
H
The aldehyde is more easily reduced
than the ketone so you must
first add a protecting group to
the aldehyde; reduce the
ketone; and finally remove
the protecting group to
regenerate the aldehyde.
+
OCH3
c)
reduction
O
1 NaBH4
+
2 H3O
2 H3O
OH
OCH3
dehydration
POCl3,
N
cold
KMnO4
O
H2/Pt
or
OH
Zn[Hg}, HCl
or
N2H4, KOH
It is important to recognize that the
syn diol is produced by cold KMnO4
oxidation of an alkene, so the alkene
must be produced at some point.
OH
cold
KMnO4
PAGE 5
ALDEHYDES/KETONES SOLUTIONS
7.
This is nucleophilic addition to a carbonyl (acid catalyzed, because the Nu is weak)
:O:
H3C
..
..:
H
H3C
C
+
H3C
C
CH3CH2
:O
OH
Cl
..
O
..
..
OCH2CH3
..
C
+
H3C
CH3CH2
H
OH
C
H3C
..
+ : Cl
..: -
H
H
:O..
CH3CH2OH2+
+
C +O
..
..
..
O
H
CH3CH2OH
+
HCl
H
CH2CH3
8. Write products of the following reactions. Show the major product but do not show
mechanisms or charged intermediates
a)
OH
O
1. NaBH4
C
CH2
H
2.
b)
CH2
H3O+
C
H
H
H
O
N2H4 , KOH
C
C
CH3
CH3
H
c)
O
C
d)
NH2OH
CH3
CH3
OH
C
CH3
+
H2O
O
O
C
N
OH
1. C6H5 MgBr
C
O- MgBr+
+
+
2. H3O
CH3
C6H6
A Grignard is a strong base
that deprotonates even very
weak acids. The Grignard
is not reactive enough to
add to a carboxylate anion.
PAGE 6
ALDEHYDES/KETONES SOLUTIONS
O
e)
1. excess LiAlH4
C
OH
C
OH
CH2OH
LiAlH4 is a better Nu than a Grignard
and can add to a carboxylate anion.
CH2OH
+
2. H3O
O
O
f)
HO
CH2
C
CH2
OH
HOOCCH2CH2COOH
acetal
O
g)
HOCH2CH2OH
HCl
h)
O
CH3CH2
i)
C
H
j)
C
CH
l)
m)
CH2
C
H
O
NH2
1 equivalent NH3
H
CH3CH
CH3CH2
H
1. C6H5MgBr
CO2
This weakened hydride, at low temp, adds
only once to esters and acid chlorides to
produce aldehydes
Recall that KMnO4 oxidizes
unsubstituted carbons in
alkenes to CO2 and
disubstituted alkene carbons
to ketones.
CO2
+
H
O
CH
C
H
Amines add to congugated
enones, to the alkene first
in 1,4 conjugate addition.
OH
NaCN, HCN
C
At low temp., Gilmans reagent
adds only once to an acid chloride
producing an alkene
C
H
O
CH3CH2
O
O
+
C
This is nucleophilic addtion by a
weak Nu to the electrophilic
carbonyl group. Acid catalysis
is needed since the Nu is weak
CH3
KMnO4 , H3O
O
k)
CH3CH

1. DIBAH at -78ºC
Cl
CH3CH2
2. H3O+
C
O
C
1. (C6H5)2 CuLi at-78ºC
CH3CH2
+
2. H3O
Cl
O
CH3CH2
O
CH3
C
Jones reagent is chromic acid
H2CrO4 in H2SO4, water and
acetone. 1° alcohols are
oxidized to carboxylic acids by it.
Jones reagent
CH2
C
H
C
N
COOH
+
2. H3O
n)
Ag(NH3)2+
HO
CH2
CH2
CH3
NO REACTION
Tollen's reagent oxidizes
only aldehydes.
PAGE 7
ALDEHYDES/KETONES SOLUTIONS
9.
CH2 COOH
a)
CH3CH2Cl
AlCl3
or
H3O+
CH3Cl
AlCl3
CH3
CHCH3
Br
CH2MgBr
Mg
ether
CH2OH
1 BH3, THF
2 NaOH, H2O2, pH8
HBr
O
O
COOH
1 equiv. (CH2=CH)2CuLi
hot
KMnO4
O
H3O+
CH
CH2
CH2 CH3
HO
O
O
C
c)
CH2
CH2
CH
NaOH
or
b)
2 H3O+
2 H3O
CH2Br
NBS
(PhCO2)2
NBS
(PhCO2)2
Cr+6, H+
+
NaCN
CH2CH3
1
1 CO2
CH2CN
O
H
H3O+
1 equiv. HOCH2CH2OH
+ HCl catalyst
O
Since the aldehyde is more reactive
it needs a protecting group before
the Grignard addtion. Finally the
protecting group is removed.
H
C
HOCH2CH2OH
O
O
C
OH
CH3CH2
O
O
H
C
H
1 CH3CH2MgBr
2
OH
1 C6H5MgBr
2 H3O+
H3O+
O
O
3°
Cr+6, H+
d)
PBr3
or
H2SO4

Br
KOH
3°
antiMarkovnikov
product
1 BH3, THF
2 NaOH, H2O2, pH8
OH
2°
HBr
PAGE 8