Electrolytic reductive coupling as a synthetic tool

Dimerization of electrochemically generated ion radicals: mechanisms and reactivity factors

“…Early applications of cyclic voltammetry to the reduction of aromatic carbonyl compounds [7] were indicative of a mechanism of pinacol formation involving the coupling of two anion radicals to give the pinacolate that protonates further to pinacol [7][8][9]. Intense mechanistic activity on reductive electrodimerization via ion radicals followed the publication of the Baizer-Monsanto electrochemical synthesis of adiponitrile from acrylonitrile and of many similar examples in the activated olefin family [10][11][12][13][14][15][16][17][18][19][20][21][22][23][24]. It is a pleasure to emphasize here the importance of the contribution of Prof. Rolando Guidelli and his coworkers to the understanding of the mechanism of activated olefin electrodimerization under the very conditions where the Baizer-Monsanto reaction is carried out.…”

Chemoenzymatic Cascades toward Aliphatic Nitriles Starting from Biorenewable Feedstocks

“…Since our goal was the development of a chemoenzymatic cascade from alcohols to nitriles without isolation of the intermediates aldehyde and aldoximes, we further improved our cascade by skipping the isolation step of the aldoxime. Taking into account that the PIPO-catalyzed oxidation can also be performed in longer chain aliphatic nitriles as solvents, e.g., in n-hexanenitrile (4), n-octanenitrile (8), or n-decanenitrile (12), which are the final products of our cascades, and as aldoxime dehydratases turned out as suitable catalysts in organic media when immobilizing them as whole cells in a superabsorber, 38 we investigated a cascade in the corresponding nitrile products as the solvent (Table 3). Accordingly, the PIPO-catalyzed oxidation has been performed in the related nitrile product as a solvent, followed by addition of a hydroxylamine hydrochloride solution in water after completion of the oxidation reaction (GC-control) to the reaction medium and stirring at room temperature until complete conversion of the aldehyde to the aldoxime.…”

“…Besides adiponitrile, other linear, aliphatic dinitriles are interesting compounds, such as octanedinitrile, which can be used as a nonclassical solvent or as a precursor for the synthesis of 1,8-octanediamine or other compounds. − Dinitriles are currently preferably synthesized by means of a double hydrocyanation of dienes or electrodimerization of acrylonitrile, which is applied for the production of adiponitrile (Scheme ). − …”