Mono-and dicyclopropylcarbonyl derivatives have been obtained by electroreduction of fluorenone, benzophenone, fluorenone mil, and benzophenone anil in the presence of l equiv of 4-bromo (or chloro) butyryl chloride (la or lb). The electrolyses are carried out in DMF or MeCN according to two methods. In method A, la (or lb) is added dropwise during the electrolysis. In method B, the total amount of la (or lb) is added at the beginning of the ...