105
2 equiv t-BuO Ot-Bu
air, 100-135 °C
+ H
excess
n
n = 0,1,2
N
R
N
R
up to 81% yield
O
O
n
n
N
R
O
R = Me, 55%
OMe, 66%
Ph, 65%
N
O
+
N
O
81% (bis:mono =1:2.2)
Scheme 4.12 Oxidative alkylation of pyridine N-oxide derivatives
5 mol% Pd (OAc) 2
3 equiv TBHP
1 equiv TBAB
100
o C
+
N
O
OR
2
R
1
H
N
O
OR
2
R
1
R
3
R
3
N
O
O
O
96%
N
O
94%
N
O
O
93%
O
N
O
76%
S
N
O
S
84%
N
O
64%
OH
N
O
O
O
77%
N
O
O
O
82%
Br
N
O
95%
O
MeO
N
O
O
O
61%
N
O
82%
O
Scheme 4.13 Oxidative C-2 alkylation of quinoline N-oxides with ethers
4 Oxidative Radical Couplings