Electrochemical reductive coupling reactions of aliphatic nitroalkenes

We describe how to selectively affect either beta-to-beta coupling (electro hydro-dimerization) or coupling between the alpha and beta centers of aliph atic nitroalkenes, the latter in a catalytic process that can be initiated both with and without electrochemistry. Of particular significance is our d iscovery of conditions that allow electrohydrodimerization to be conducted using aliphatic nitroalkenes bearing acidic protons. Thus, one can affect a t will, either a catalytic alpha-to-beta coupling or an electrohydrodimeriz ation using substrates that bear acidic protons, as well as those that do n ot. We also describe both voltammetric and ESR studies of the simple 1 -nit ro-3,3-dimethyl-1-butene, as well as the results of quantum mechanical calc ulations that shed light upon the nature of radial anions derived from elec tron deficient olefins. Both calculation and experiment suggest: that the r eluctance of these materials to undergo electrohydrodimerization can be cor related with the low electron density on carbon and the corresponding high value on oxygen, of the radical anion.