CHAPTER 16 : ALDEHYDES +
LETONES
nucleophile (LB)
structure and
bonding :
H
--
P
Formaldehyde
H
O
R-H
aldehyde
R- RI
Leton ?
1)
arul
[ electrophile [LA]
,vinyl ,
R ,R
= alkul
nomenclature :
-
aldenydes :
i
acyclic
* aldenyde takes it it + I
priority 3-methylbutanal 3-methyl but-z-enal
L (E) 3-isopropyl-4-methyl 3-isopropyl-3-methyl
-
* Al W
pentane dial
pens-z-encal
-
=
* double bond > R >
-
two
↑
CHO groups
groups or more
ALDEHYDES
· · t i
Cyclic aldenydes :
* -
e is retained
* -
carbaldenude
N
&
Carbaldenyde gets 6-(tert-butyl) Cyclonex-3-ene 2 (tert-butyl) Cycloneyone
Gimehuhezen-methylcyclone
-
lowest then double a
bond thensubst
-Denyde Carbadenycle 3-dicarbaldehyde 1
, -
>
-
acyclic ketones :
* -
* retain-e
one
for z or more
h
4 methyl pentan-z
-
E
4-methulpent---en-2-one
Mr
3-Dimehheptaea
3, 3-dimethylheptane-2
mu 3 6-dione
* distrione ,
- L
,
LETONES
P
↑
cyclic betones :
* alkene > subst
*retain-efor two or
more
.
I ·
6-isopropylcyclonex-z-ene Zisopropylcyclohexane
6-isobutuonex-T-ene--isobutylydonexane-lin
a
-
-
examples :
ii
i s #
3-hydroxy-z-methylpentance 2-methyl-3-oxopentanyl-acetylcyclopropane-1-carbaldehyde -
Ketone Letone on
ring
addition of carbon nucleophiles
> formation of new c-cbonds
-
5- St S St
-
R-= O N= c R-Mq-4 R-Li
acetylide Cyanide Grignard organolithium
mechanism :
↑
R-RI · Nun Ho ,
addition of Grignard organolithium reagents
+
Reagents : 1 .
R-MgBr Etz0 2 HCl , H20
, .
(He0t)
Formaldehyde > -
1Alcohols
G MgBr
R-MgBr d- C attacks elect
·
2
·
.
↑
Hs0 protonates
- · +
+ -
H H
electSnuc.MgBr 10 alconol
Aldenudes >
-
Zo alcohols
c-cbond
2
Oh
DY
new
I
FEEIT 2 alcono
ketones > 3 alcohols
°
-
↑to ,
1 -MgC
.
newcons
-
30 alcond
,addition of anions of terminal alkynes · NaNH2 THE deprotonates
,
Reagents : 1 NaNH2 , TH) 2 Ketone 3 HC , HzO
. . . to make nucleophile
· Letone gets attacked
example :
-
NaDO : j new ccbond ·
H30" protonates
, Ho
[ L , ,
(chiral center created)
addition of hydrogen cyanide ·
EQ favors product for aldenydes
and aliphatic ketones
Reagents : KCN +
H20 ·
EQ favors left for many aryl
PH 10 =
new
C-cond Letones
PH
#
example :
mechanism :
new
c-bond
:
D H CN ①
⑤
II
: n
in-H
the witting reaction
> formation of new c= c
-
bonds from aldehydes/betones
Reagents : PPH3 Strong base +
example : newc = (bond i ·
ylide attacks aldenyde/betone
or
"
New c-bond
·
- · shift electrons/bonds for alkene
"ylide" i n Ph
mechanism :
prepare --I
↳ ·
stabilized ylides
SNz Yield E
need d-h
isolated
methyl 10 or 20 ,
alkul halice
2) reaction or betone
c-bond
with an aldehyde new
-
new c-bond
pr-Ph alkene product
collapses
Stereoselectivity :
z(major)
+ Zi
Emp
E
Horner-wadsworth-emmons ryn
Reagents : stabilized phosphate carbanion + Et=0
example :
-Creato
E
Pe
Meo-p-O oyieldst-alkene
Ome w/resonance stability
aldehyde stabilized phosphate
Carbanion
mechanism :
m
1) formation of stabilized phosphate carbanion
"Pote
2) reaction
+ credia >
betone
o
with an aldehyde or
E
-
o +
alkene product
new C-Cbond
collapses
example :
-
&
·
I
&
T
·
LETONES
nucleophile (LB)
structure and
bonding :
H
--
P
Formaldehyde
H
O
R-H
aldehyde
R- RI
Leton ?
1)
arul
[ electrophile [LA]
,vinyl ,
R ,R
= alkul
nomenclature :
-
aldenydes :
i
acyclic
* aldenyde takes it it + I
priority 3-methylbutanal 3-methyl but-z-enal
L (E) 3-isopropyl-4-methyl 3-isopropyl-3-methyl
-
* Al W
pentane dial
pens-z-encal
-
=
* double bond > R >
-
two
↑
CHO groups
groups or more
ALDEHYDES
· · t i
Cyclic aldenydes :
* -
e is retained
* -
carbaldenude
N
&
Carbaldenyde gets 6-(tert-butyl) Cyclonex-3-ene 2 (tert-butyl) Cycloneyone
Gimehuhezen-methylcyclone
-
lowest then double a
bond thensubst
-Denyde Carbadenycle 3-dicarbaldehyde 1
, -
>
-
acyclic ketones :
* -
* retain-e
one
for z or more
h
4 methyl pentan-z
-
E
4-methulpent---en-2-one
Mr
3-Dimehheptaea
3, 3-dimethylheptane-2
mu 3 6-dione
* distrione ,
- L
,
LETONES
P
↑
cyclic betones :
* alkene > subst
*retain-efor two or
more
.
I ·
6-isopropylcyclonex-z-ene Zisopropylcyclohexane
6-isobutuonex-T-ene--isobutylydonexane-lin
a
-
-
examples :
ii
i s #
3-hydroxy-z-methylpentance 2-methyl-3-oxopentanyl-acetylcyclopropane-1-carbaldehyde -
Ketone Letone on
ring
addition of carbon nucleophiles
> formation of new c-cbonds
-
5- St S St
-
R-= O N= c R-Mq-4 R-Li
acetylide Cyanide Grignard organolithium
mechanism :
↑
R-RI · Nun Ho ,
addition of Grignard organolithium reagents
+
Reagents : 1 .
R-MgBr Etz0 2 HCl , H20
, .
(He0t)
Formaldehyde > -
1Alcohols
G MgBr
R-MgBr d- C attacks elect
·
2
·
.
↑
Hs0 protonates
- · +
+ -
H H
electSnuc.MgBr 10 alconol
Aldenudes >
-
Zo alcohols
c-cbond
2
Oh
DY
new
I
FEEIT 2 alcono
ketones > 3 alcohols
°
-
↑to ,
1 -MgC
.
newcons
-
30 alcond
,addition of anions of terminal alkynes · NaNH2 THE deprotonates
,
Reagents : 1 NaNH2 , TH) 2 Ketone 3 HC , HzO
. . . to make nucleophile
· Letone gets attacked
example :
-
NaDO : j new ccbond ·
H30" protonates
, Ho
[ L , ,
(chiral center created)
addition of hydrogen cyanide ·
EQ favors product for aldenydes
and aliphatic ketones
Reagents : KCN +
H20 ·
EQ favors left for many aryl
PH 10 =
new
C-cond Letones
PH
#
example :
mechanism :
new
c-bond
:
D H CN ①
⑤
II
: n
in-H
the witting reaction
> formation of new c= c
-
bonds from aldehydes/betones
Reagents : PPH3 Strong base +
example : newc = (bond i ·
ylide attacks aldenyde/betone
or
"
New c-bond
·
- · shift electrons/bonds for alkene
"ylide" i n Ph
mechanism :
prepare --I
↳ ·
stabilized ylides
SNz Yield E
need d-h
isolated
methyl 10 or 20 ,
alkul halice
2) reaction or betone
c-bond
with an aldehyde new
-
new c-bond
pr-Ph alkene product
collapses
Stereoselectivity :
z(major)
+ Zi
Emp
E
Horner-wadsworth-emmons ryn
Reagents : stabilized phosphate carbanion + Et=0
example :
-Creato
E
Pe
Meo-p-O oyieldst-alkene
Ome w/resonance stability
aldehyde stabilized phosphate
Carbanion
mechanism :
m
1) formation of stabilized phosphate carbanion
"Pote
2) reaction
+ credia >
betone
o
with an aldehyde or
E
-
o +
alkene product
new C-Cbond
collapses
example :
-
&
·
I
&
T
·
