Synthese asymetrique par voie electrochimique. Etude de l'influence des differents parametres sur le rendement optique

Abstract

The influence of different factors which could affect the optical yield of an asymmetric reduction, made by an electrochemical method in the presence of inducing agents, has been investigated in the case of the electrolysis of phenylglyoxylic acid at a mercury cathode. Maximum optical yield is obtained with tiny amounts of a suitable alkaloid; the ability of such compounds to induce optical activity depends both on its adsorption at the mercury and the nature of the substrate. Electrolysis must be done with relatively low current density and with efficient stirring of the mercury pool in order to regenerate usable inducing agent. Subject to the previous determination of the optimum pH, the optical yield of the reaction studied may exceed 20 per cent. The rate determining step of the induction would be the formation of an adsorbed complex between the carbanion and the inducing agent, the protonation of which occurring with at least partial retention of the carbanion configuration.