Ultrasonic effects on electroorganic processes. Part 25. Stereoselectivity control in cathodic debromination of stilbenedibromides

Ultrasonic effects on the cathodic debromination of stilbenedibromides on a platinum cathode was examined. Current efficiency and stereoselectivity for trans-stilbene, which was formed along with cis-stilbene in the cathodic debromination of stilbenedibromides, were significantly increased under ultrasonication with an intensity over the ultrasonic cavitation threshold. This ultrasonic effect is rationalized as due to mass transport promotion in the electrode-electrolytic solution interface. A mechanism for the ultrasonic effect is discussed in detail on the basis of the reaction pathway of the debromination of stilbenedibromides.