71707-68-1Relevant articles and documents
Interconversion and rearrangement of radical cations. Part 2. Photoinduced electron transfer and electrochemical oxidation of 1,4-bis(methylene)cyclohexane
Lijser, H. J. P. de,Arnold, Donald R.
, p. 1369 - 1380 (2007/10/03)
The photoinduced electron transfer and electrochemical oxidation of 1,4-bis(methylene)cyclohexane (2) in acetonitrile have been studied in the presence and absence of a nucleophile (methanol).The photoinduced electron transfer reactions of 2 in acetonitrile-methanol solution with 1,4-dicyanobenzene (8) as the electron acceptor gives two products: 4-(methoxymethyl)-1-methylenecyclohexane (16) and 4-(4-cyanophenyl)-4-(methoxymethyl)-1-methylenecyclohexane (17).These products arise from nucleophilic attack on the radical cation followed by either reduction and protonation or combination with the radical anion of the electron acceptor, 1,4-dicyanobenzene (8.-).These results are in accord with the proposed mechanism of the photochemical nucleophile-olefin combination, aromatic substitution (photo-NOCAS) reaction.In the absence of a nucleophile, the photoinduced electron transfer reaction of 2 gives rise to several interesting and unexpected products 18-25 which result from complex reaction mechanisms involving radical, ionic and radical ion intermediates.The electrooxidation of 2 in acetonitrile in the presence of methanol leads to products 27-35.Under these conditions the radical cation 2.+ reacts with the nucleophile followed by a second oxidation and subsequent reactions leading to products (electrochemical-chemical-electrochemical, ECE).One of the products (28) is the results of protonation of 2 followed by nucleophilic attack.The electrochemical oxidation of 2 in acetonitrile (no methanol) yields 2.+ which is deprotonated and then further oxidized to give 39-43.These products arise from ionic intermediates (ECE); oxidation of 2 all the way to aromatic compounds was observed in 39-41.In none of these experiments was there any evidence for the formation of cyclized products, nor was there any indication of carbon-carbon bond cleavage in 2.+.The products are consistent with the initial formation of the intermediate radical cation.The products as well as the possible mechanisms of formation of these species are discussed.
