Investigation Towards the Asymmetric CBS‐Catalysed Reduction of Aryl Methyl Ketones with Electrochemically in Situ Generated BH3

Abstract The aim of this investigation was to explore the possibility to perform an asymmetric reduction, utilising a CBS ‐type catalyst, of prochiral aryl methyl ketones under electrochemical conditions to generate the needed BH 3 upon oxidation of NaBH 4 with in situ generated I 2 in the anode compartment. Therefore, various electrochemical parameters were optimised to conduct the desired formation of the chiral secondary alcohols in high to quantitative yields with a high stereochemical induction, although the catalyst loading had to be chosen relatively high to concur with the racemic reduction of the ketones by the electrogenerated BH 3 .