Chemistry Reference
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was developed for the mild aerobic oxidative esterification of various
aromatic and heteroaromatic aldehydes.
51
The in situ activation of
Ru(TPFPP)(CO) [TPFPP
ΒΌ
tetrakis(pentafluorophenyl)porphyrin] (Equation 3.4)
with m-CPBA provided a ruthenium species capable of catalyzing the oxidation
of alcohols with molecular O
2
.
52
d
n
4
r
4
n
g
|
0
F
5
C
6
C
6
F
5
F
5
C
6
C
6
F
5
N
N
O
m
CPBA (2 eq.)
Ru
N
Ru
N
N
N
(3.4)
CO
O
N
N
C
6
F
5
C
6
F
5
F
5
C
6
F
5
C
6
Ru(TPFPP)O
2
Ru(TPFPP)(CO)
Based on the chemoselective aerobic oxidation of primary alcohols
catalyzed by Ru-salen complexes,
53
kinetic resolution of racemic secondary
alcohols
54
and desymmetrization of meso-diols
55
were realized by using a chiral
(nitrosyl)ruthenium(salen) complex under photo-irradiation (Scheme 3.2).
56
OH
O
H
O
1
(2.0 mol%),
hv
+
Ph
Ph
Ph
PhCl, r.t., air
91%
ee
(61% conversion)
O
H
P
h
Ph
.
2
(2.0 mol%),
hv
OH
HO
O
CHCl
3
, r.t., air
Ph
Ph
81%
ee
, 82%
OH
OH
OH
3
(2.0 mol%),
hv
O
CHCl
3
, r.t., air
80%
ee
, 67%
(R)
R
R
N
NO
N
Ru
1:
R = H, Ar = Ph, X = Cl
O
O
X
Ar
Ar
2:
R = Me, Ar = Ph, X = Cl
(R)
3:
R = Me, Ar = 4-PhC
6
H
4
, X = OH
Scheme 3.2 Ru(salen) complexes used as catalysts
for aerobic asymmetric
oxidations.
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