Studien zum vorgang der wasserstoffübertragung—33. Zur kenntnis des aufbaus der elektrochemischen doppelschicht. Die asymmetrische elektrochemische reduktion einiger alkyl-phenyl-ketone in gegenwart optisch aktiver leitsalze

Abstract

Alkyl phenyl ketones have been reduced in the presence of optically active supporting electrolytes ( e.g. derivatives of ephedrine, pseudoephedrine and desoxyephedrine) to optically active alkyl-phenylcarbinols and optically inactive pinacols. The dependence of product composition and degree of asymmetric induction on the structure of the supporting electrolyte and the depolarizer was determined. Increasing size of the alkyl group in the alkyl-phenyl-ketone favours higher carbinol yields and diminishes the degree of optical activity. The functional groups of the supporting electrolyte also exercise a noticeable influence on the d,l/ meso ratio in pinacol formation. In order to explain these combined effects, and taking intermolecular interactions into account, a model has been proposed of an adduct between the supporting electrolyte and depolarizer (or depolarizer radical anion). These results can be taken, with some care, as a contribution to the understanding of the adsorption of organic molecules in the double layer.