| Research Abstract |
Dipole inversion methodology of palladium complexes in electroreductive media has been studied. Cyclic volta of sigma-aryl palladium complex shows one two electron reduction and two oxidation peaks, suggesting the following sequential reactions :
Ar-Pd-X +2e^- * Ar-Pd^- + X^-
Ar-Pd^- * Ar^- + Pd^0
sigma-Aryl palladium anion and/or aryl anion can be react with aryl halides and appropriate electrophiles (CO_2), affording biaryls, arenecarboxylic acids, and others. Cross coupling between different aryl halides can be achieved by electroreduction of sigma-aryl palladium complex and aryl halide. On the other hand, electroreduction of propagyl acetates in the presence of palladium catalyst afforded the corresponding allene compounds, wherein, dipole inversion of the intermediary allenyl palladium complex would proceed through two electron reduction.
As an extension work, we investigated bimetal redox systems e.g., alkenyltin/palladium complex and alkenyltin/copper(I) salts, and found one-electron transfer system providing alkenyl radical equivalents.
In conclusion, the above preliminary studies may open new entries to a new methodology for generating unique anionic species, e.g., aryl palladium anion, aryl anion, allenyl anion, and their equivalents.
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