123
3. The addition of the radical to alkene produces another radical intermediate.
4. The intramolecular radical cyclization of intermediate takes place to form radical
intermediate.
5. The R-O abstracts one H from intermediate to form oxindole products.
R 1
R 2
NC
+
R 1
R 2
N
R'
R
OH
R'
H
R
OH
5 mol% Cu 2 O
3 equiv DCP
110 °C, 11 h
R
1
R 2
N
R'
R
OH
Scheme 4.38 Oxidative radical C-C coupling between 2-aryl phenyl isonitrile and alcohols
O
R'
O
R
R O
O
O
ROH
O
O
H
NC
N
O
O
N
O
O
H
N
O
O
ROH
R
1
R
2
NC
+
R
1
R
2
N
1 equiv TBPB
Reflux
O
O
O
O
R
1
= H, Me, OMe, F, Cl, NO 2 ;
R
2
= H, Me, OMe, etc.
R O
Scheme 4.39 Oxidative coupling between 2-aryl phenyl isonitrile and dioxane
4 Oxidative Radical Couplings