Heteroatom nonbonding orbitals, P position

A. Interaction of C-MR3 with heteroatom nonbonding orbitals at the P position... 

The C-Sn a orbital also interacts with a neighboring nonbonding p orbital of heteroatoms, and this interaction decreases the oxidation potential significantly [128,129]. It should be noted that the oxidation potentials of a-heteroatom-substituted tetraorganos-tannanes are less positive than those of carbon nucleophiles such as allylsilanes and enol sily ethers. Consequently, such carbon nucleophiles can be used for the electrochemical oxidation of a -heteroatom-substituted tetraorganostannanes to achieve the carbon-carbon bond formation. In fact, various intermolecular carbon-carbon bond formation reactions have been developed using a-heteroatom-substituted tetraorganostannanes [130-132]. 

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