Chemistry Reference
In-Depth Information
Tab. 4.52.
Oxidation of alcohols using triphosgene.
Alcohol
Product
Yield (%)
a
Method A
Yield (%)
b
Method B
n-Heptanol
Heptanal
82
-
n-Octanol
Octanal
91
95
Geraniol
Geranial
95
95
Citronellol
Citronellal
95
85
n-Dodecanol
Dodecanal
90
100
2-Phenyl-1-propanol
2-Phenylpropanal
75
38
2-(p-Anisyl)ethanol
2-(p-Anisyl)ethanal 1889
79
27
2-Phenylethanol
2-Phenylethanal
51
23
4-Methoxybenzyl alcohol
4-Anisaldehyde
95
-
Cinnamyl alcohol
Cinnamaldehyde
95
97
3-Pentanol
3-Pentanone
90
-
2-Hexanol
2-Hexanone
92
-
3-Methylcyclohexanol
3-Methylcyclohexanone
92
100
2-Octanol
2-Octanone
95
98
3-Methyl-2-heptanol
3-Methyl-2-heptanone
78
-
5-Nonanol
5-Nonanone
68
-
Benzoin
Benzil
95
95
a
Method A: triphosgene/DMSO;
b
Method B: oxalyl chloride/DMSO
[1319].
CH
3
O
l
Cl
H
3
C
Cl
O
l
Cl
CH
2
Cl
2
- 78 °C
+
Cl
Cl
S
S
O
+
H
3
C
O
O
Cl
H
3
C
Cl
O
O
Cl
1887
triphosgene
CH
3
O
Cl
S
H
3
C
O
l
1888
78
C, anhydrous DMSO (0.5 mL, 7.06 mmol) was added dropwise with stirring.
After 5 min, 2-( p-anisyl)ethanol (0.403 g, 2.63 mmol) in dry dichloromethane
(10 mL) was added dropwise. The mixture was stirred at
78
C for an additional
15 min, then triethylamine (2.0 mL, 14.28 mmol) was added, and the reaction
mixture was allowed to warm to room temperature (
10 min). It was quenched
with water (50 mL) and the organic phase was washed sequentially with 5% aq.
HCl (50 mL), 5% aq. NaHCO
3
(50 mL), saturated NaCl solution, and water. The
final organic layer was dried over Na
2
SO
4
, subjected to flash chromatography (15 g
of silica gel), and the solvent was removed under reduced pressure to give the
aldehyde 1889 in 79% yield.
@
