Oxidative Deprotection of Trimethylsilyl Ethers
1453
TABLE IV Comparison of Some of the Results Obtained by the
Oxidative Deprotection of Trimethylsilyl Ethers Using (CTA)
with those Using Other Oxidants
2
2 8
S O
Reagent/ Time Reaction
Substrate (min) Conditions Yield (%) Ref
Reagent
,6-DCPFCa
Substrate
2
p-MeOC6H4CH2OSiMe3
1:1
1:1
6
5
CH3CN,
r. t.
96
100
94
93
90
95
93
80
94
95
92
95
17e
17c
17g
17h
17d
17f
(
C6H5)2CHOSiMe3
p-MeOC6H4CH2OSiMe3
C6H5)2CHOSiMe3
p-MeOC6H4CH2OSiMe3
C6H5)2CHOSiMe3
p-MeOC6H4CH2OSiMe3
C6H5)2CHOSiMe3
p-MeOC6H4CH2OSiMe3
C6H5)2CHOSiMe3
p-MeOC6H4CH2OSiMe3
C6H5)2CHOSiMe3
QFCb
30 CH3CN,
96 r. t.
300 CH3CN,
18 reflux
45 CH2Cl2,
(
BTPPCd
1:1
(
3
-CPCCc
2:1
(
120
5
7
reflux.
CH3CN,
reflux
[
BTPPPODS]
1:1
(
ATPPDe
1.15:1
15 CH3CN,
20 reflux
(
a2,6-Dicarboxypyridinium fluorochromate; b quinolinium fluorochromate;
c3-carboxypyridinium chlorochromate; benzyltriphenylphosphonium peroxodisulfate;
d
e
and allyltriphenylphosphonium peroxodisulfate.
was washed with MeCN (20 mL). The filtrates were combined and the
solvent was evaporated. The resulting crude material was purified by
chromatography using silica gel and an appropriate eluent (n-hexane /
EtOAc, 10:1). The pure carbonyl compounds were obtained in 70–97%
yields (Tables II and III).
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