175
which was oxidized by excited eosin Y* to generate sulfonyl radical 68. This radical
intermediate was trapped by an α-methylstyrene derivative to form the target product allylic sulfone via a series of electron and proton transfer processes [16].
+ H 2
N
N
Co
N
N
O
O
H
O H
O H
Cl
N
Co(dmgH) 2 (p-NMe 2 Py)Cl
N
H
S
R
H
-e - , -H
+
N
S
R
-H
+
62
63
64
N
S
R
H
N
S
R
-e -
61
3 mol % Ru(bpy) 3 (PF 6 ) 2
8 mol % Co(dmgH) 2 (p-NMe 2 Py)Cl
1.0 equiv sodium-Gly
0.4 equiv DMAP
CH 3 CN
blue LEDs
N
Scheme 5.27 Photocatalytic intramolecular annulation of N-phenylbenzothioamides
+
N
H
S
H
N
S
64a
61a
3 mol % Ru(bpy) 3 (PF 6 ) 2
2 equiv oxidant
1.0 equiv sodium-Gly
0.4 equiv DMAP
CH 3 CN, blue LEDs
N
H
O
H
61a'
entry
a
oxidant
yield (%)
b
64 a
61a'
1 b
2
c
3
4
-
O 2
K 2 S 2 O 8
H 2 O 2
99
0
7
49
26
38
16
17
a Reaction conditions: 61a (0.35 mmol), Ru(bpy) 3 (PF 6 ) 2 (3 mol %), oxidant (2 equiv), sodium-Gly (1.0 equiv) and
DMAP (0.4 equiv) were added in CH 3 CN (2 mL) under irradiation of 23W white fluorescent lamp for 12 h at rt.
b Co(dmgH) 2 (4-NMe 2 Py)Cl (8 mol %) was used in place of oxidant. c 1 atm O 2 was used.
Scheme 5.28 Comparison between photo/cobalt and photo/oxidant systems
5 Fourth-Generation Oxidative Cross-Coupling Reactions
which was oxidized by excited eosin Y* to generate sulfonyl radical 68. This radical
intermediate was trapped by an α-methylstyrene derivative to form the target product allylic sulfone via a series of electron and proton transfer processes [16].
+ H 2
N
N
Co
N
N
O
O
H
O H
O H
Cl
N
Co(dmgH) 2 (p-NMe 2 Py)Cl
N
H
S
R
H
-e - , -H
+
N
S
R
-H
+
62
63
64
N
S
R
H
N
S
R
-e -
61
3 mol % Ru(bpy) 3 (PF 6 ) 2
8 mol % Co(dmgH) 2 (p-NMe 2 Py)Cl
1.0 equiv sodium-Gly
0.4 equiv DMAP
CH 3 CN
blue LEDs
N
Scheme 5.27 Photocatalytic intramolecular annulation of N-phenylbenzothioamides
+
N
H
S
H
N
S
64a
61a
3 mol % Ru(bpy) 3 (PF 6 ) 2
2 equiv oxidant
1.0 equiv sodium-Gly
0.4 equiv DMAP
CH 3 CN, blue LEDs
N
H
O
H
61a'
entry
a
oxidant
yield (%)
b
64 a
61a'
1 b
2
c
3
4
-
O 2
K 2 S 2 O 8
H 2 O 2
99
0
7
49
26
38
16
17
a Reaction conditions: 61a (0.35 mmol), Ru(bpy) 3 (PF 6 ) 2 (3 mol %), oxidant (2 equiv), sodium-Gly (1.0 equiv) and
DMAP (0.4 equiv) were added in CH 3 CN (2 mL) under irradiation of 23W white fluorescent lamp for 12 h at rt.
b Co(dmgH) 2 (4-NMe 2 Py)Cl (8 mol %) was used in place of oxidant. c 1 atm O 2 was used.
Scheme 5.28 Comparison between photo/cobalt and photo/oxidant systems
5 Fourth-Generation Oxidative Cross-Coupling Reactions