ABSTRACT
The oxidation potentials of benzylsilanes are also less positive than those of the corresponding aromatic hydrocarbons and tetraorganosilanes owing to the a-rr interaction. The preparative electrochemical oxidation of benzylsilanes results in the cleavage of the C-Si bond and the introduction of a nucleophile on the carbon [110]. The following example demonstrates that the benzylic C-Si bond is cleaved selectively without affecting the aromatic C-Si bond:
d. Activation by a-n Interaction. The C-Si a orbital interacts with a neighbouring nonbonding p orbital of heteroatoms such as oxygen, nitrogen, sulfur, and phosphorous (a-n interaction). Because of the a-n interaction, the oxidation potentials of a-heteroatom-substituted tetraorganosilanes are less positive than those of the corresponding simple heteroatom compounds and tetraorganosilanes [ 114, 115]. Table 3 demonstrates that the oxidation potentials of a-heteroatom-substituted organosilicon compounds exhibit less positive oxidation potentials than ,B-heteroatom-substituted organosilicon compounds, indicating the importance of a-n interaction.
