Publication 526

Contribution from the Laboratoire d'Electrochimie Moléculaire, Unité Mixte de Recherche Université - CNRS No 7591, Université de Paris 7 - Denis Diderot, 2 place Jussieu, 75251 Paris Cedex 05, France

The synthesis of a series of chlorodifluoromethylated ketones 1–6 is presented and the cyclic voltammetry of the reductive cleavage of these ketones was investigated, in N,N-dimethylformamide (DMF), at an inert electrode. Indirect electrochemical reduction (by means of an electrogenerated anion radical) in acetonitrile (CH₃CN) or in N,N-dimethylformamide (DMF), of the naphthalene-derived chlorodifluoroacetylated compounds 1 and 2 in the presence of the olefinic substrates 7–10, yields new gem-difluoro heterocyclic compounds 11–16 after intramolecular cyclisation of a ,-difluoroalkyl radical. Aromatic nucleophilic substitution of ,-difluoroketones 12 and 13, in anhydrous dimethylsulfoxide, with several tetramethylammonium salts of imidazole as nucleophiles, proceeds under mild conditions to give the corresponding nitrogen–nitrogen exchanged products 17–23 in moderate to good yields