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Reactivity of carbonyl derivatives is regulated by the balance ff the inductive and resonance effects. - PowerPoint PPT Presentation
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Derivative Substituent(X)
13 C δ (ppm)
acyl chloride -Cl 170.3
anhydrides -O-CO-R167
t wosignals inasymmetrical case
cyclobutanone - R (cycli )c 219esters -OR 171
alde hyde aliphatic -H 202acids -OH 173-181
ke tone aliphatic -R 206alde hyde aromatic -H 192ke tone aromatic -Ar 197
amides -NHR 173acyl anion -O- 185
X
O
X
O
X
O
inductive effectdedcreases bond length
increase energy (reactivity)
resonance effectincreasesbond length
decreasesenergy (reactivity)
Reactivity of carbonyl derivatives is regulated by the balanceff the inductive and resonance effects.
Derivative Substituent(X)
υ (cm-1) effect
acyl fluoride -F 1870 resonance(unreactive)
acyl chloride -Cl 1815-1790 inductive
anhydrides -O-CO-R1820-1770(averag e of two
bands)inductive
cyclobutanone - R (cycli )c 1785 rin g strainesters -OR 1750-1730 resonancealdehyde(aliphatic)
-H 1730 inductive
acids -OH 1715-1680 resonanceketone
(aliphatic)-R 1715 inductive
aldehyde(aromatic)
-H 1705 resonance
ketone(aromatic)
-Ar 1690-1680 resonance
amides -NHR 1690-1650 resonanceacyl anion -O- 1650-1550 resonance
OH
O
Conversion of Acyl Halides to all other carbonyl derivatives
SOCl2Cl
O
+OH
OH
O
OOH
R3N
R3NH+Cl-
(CH3)2NH2+Cl-
(CH3)2NH
N
O
+
+
ether
ether
1°
3°
O-Na +
O
O
O O
Na+Cl-+
Use of tertiary amines in irreversible acyl transfer reactions
Cl
O
+
O-
O
O
+
+
Cl-
OH
OHO
ClH
O-
OCl
H
OH
OH OH
H
O
OOH
H
NO
OOH
N
H
ether
precipitate
OH
O
Conversion of Acyl Halides to ketones
SOCl2Cl
O
+ MgBr
O
ether
OH
O
SOCl2Cl
O
+ CuLi
2
ether
O
to α,β-unsaturated ketones
OH
O
Reduction of Acyl Halides to aldehydes and alcohols
SOCl2Cl
O
+ MgBr
OH
ether
1. LAH / etherCl
O
+
OH
2 mol
2. H3O+
2. H3O+
PCC H
O
Cl
O
H
O
O H-
Al
O
O
Li+
Formation of 3° alcohols is a stepwise process using 2 mol reagent
Cl
O
+ Cl
OMgBr
O
+
+ Mg(OH)Br2. H3O
+
Cl
OMgBr
Cl-
O OH
MgBr
MgBr
Anhydrides are used as acylating agents for OH and NH groups
O
O
+O
O-
+
OH
O
H
-O
O
CO2HO
O
CO2H
O
O-
O
H
O
CO2H
H2OO
O
O
O
CO2H
O
O
O
O
CO2H
O
O
CO2H
acetylsalycilic acid
salycilic acid
Ester functional group is first reduced to an aldehyde, then to alcohol.
O
O
HOH2C
Al-
H
H
H
H+
O
OAl-
H
H
H
H
O
OAl-
H
H
H
HH
O
+ Al-
H
H
H
OCH3
H
O
AlH4-
4 mol 4 mol+ H3AlO3H3O
+
Formation of 3° alcohols is a stepwise process using 2 mol reagent
H3CO
O
+H3CO
OMgBr
O
+
+ Mg(OH)Br2. H3O+
H3CO
OMgBr
-OCH3
O OH
MgBr
MgBr
Preparation of 1,4- and 1,5-difunctional compounds.Baeyer-Villiger oxidation of ketones.
CF3CO3H
O
O
1. LAHO
PhCO3HO
O
O2. H3O
+ HOOH
CF3CO3H1. LAH
O
O
O2. H3O
+ HO
OH
1
4
14
1. DIBAH
2. H3O+
HO
1
O5
H
Baeyer-Villiger oxidation of ketones.
O
O
PhCO3HO
1. 2 mol PhMgBr
2. H3O+ HO
15
HO
O
O
1
2
3
4
5
1. 2 PhMg Br /ether
2. H3O+HO OH
Ph
Ph
5
4
3
21
1.
O
O
δ+
δ-
+ Ph Mg Brslow O
Ph O Mg2 Br
O
Ph O Mg2 Br1
2
3
4
5
fast Ph
O
12
34
5
O Mg2 Br
2.
HO OH
Ph
Ph
5
4
3
21
Ph
O
O Mg2 Br
Ph Mg Br+
Ph
1
2
3
4
5
O Mg2 Br
PhOMg2Br
4.
3.Ph
1
2
3
4
5
O Mg2 Br
PhOMg2Br
H3O+
