177
The above reaction has high selectivity for C(sp
2
)-H bond activation; on the contrary, C(sp
3
)-H bonds were not affected. This is because the arene radical cation
intermediate plays an important role in the selective C(sp
2
)-H activation in this system. Under oxidative reaction conditions, very small amounts of amination products
were generated in the presence of various oxidants. As a result, the CCHE reaction
Scheme 5.31 Proposed mechanism for photocatalytic amination or hydroxylation of benzene
Scheme 5.30 Photocatalytic direct hydroxylation and amination of the inert C-H bonds of
benzene
5 Fourth-Generation Oxidative Cross-Coupling Reactions
The above reaction has high selectivity for C(sp
2
)-H bond activation; on the contrary, C(sp
3
)-H bonds were not affected. This is because the arene radical cation
intermediate plays an important role in the selective C(sp
2
)-H activation in this system. Under oxidative reaction conditions, very small amounts of amination products
were generated in the presence of various oxidants. As a result, the CCHE reaction
Scheme 5.31 Proposed mechanism for photocatalytic amination or hydroxylation of benzene
Scheme 5.30 Photocatalytic direct hydroxylation and amination of the inert C-H bonds of
benzene
5 Fourth-Generation Oxidative Cross-Coupling Reactions