Six alpha-haloketones adsorbed on a graphite powder cathode were reduced in the presence of benzaldehyde using undivided cell, inert anode and aqueous electrolyte. High yields of aldol coupling product were obtained from 2-chloropinacolone in the presence of catalytic amounts of silver. For the corresponding bromo compound, the reaction was much less satisfactory. Chloroacetone gave moderate yields of the alpha,beta-unsaturated coupling product. 2-Chlorobutanone produced two main products in low yield: the expected aldol and the corresponding 1,3-diketone. With 2-bromopropiophenone and 2-bromoisobutyrophenone no coupling with benzaldehyde was observed but only reductive dehalogenation. The results can be interpreted in terms of a carbanionic intermediate generated by a two-electron transfer. (C) 2012 Elsevier Ltd. All rights reserved.