Synthese asymetrique par voie electrochimique—VI. Etudes en double induction

The electrochemical reduction of (−) menthyl phenylglyoxylate is performed at a mercury cathode in the presence of various additional compounds. These compounds may be more or less adsorbed, chiral or not and more or less efficient as proton donating species. This study shows that optical yield depends on the working potential and the proton donating ability of the solution. Experimental results are in good agreement with the hypothesis of a kinetic competition between the electric field effects (inversion of the intermediate carbanion and its repulsion towards the solution) and protonation of this carbanion either in the near vicinity of the electrode or in the bulk of the solution.