83242-06-2Relevant articles and documents
Benzyl radicals from toluene by photosensitization with naphthalene-1,4- dicarbonitrile - Benzylation and hydroxymethylation of unsaturated compounds
Mella, Mariella,Fagnoni, Maurizio,Albini, Angelo
, p. 2137 - 2142 (2007/10/03)
In aprotic media, photoinduced electron transfer from toluene to 1,4- naphthalenedicarbonitrile (DCN) is followed by in-cage proton transfer and radical coupling. However, in the presence of a protic co-solvent, the radical ions diffuse out of the cage and deprotonation of the toluene radical cation takes place from the free solvated species. With (BuOH, this results in reductive benzylation of DCN through coupling of benzyl radicals with DCN-·. With MeOH, secondary hydrogen abstraction by PhCH2- yields hydroxymethyl radicals, which couple with DCN-·. Both benzyl and hydroxymethyl radicals are efficiently trapped by electrophilic alkenes. Thus, in the presence of dimethyl maleate, DCN-photosensitized benzylation - or hydroxy-methylation - of the substrate occurs through direct activation of the C-H bond. The same reaction has been accomplished with acrylonitrile, albeit with a lower yield.
Photoinduced electron-transfer reactions of arylmethyl-substituted 14 group compounds: Photoarylmethylation and photooxygenation
Tamai,Mizuno,Hashida,Otsuji
, p. 3747 - 3754 (2007/10/02)
Photoreactions of arylmethylsilanes, -germane, and -stannane with 1,4- dicyanonaphthalene (DCN) and 9, 10-dicyanoanthracene (DCA) were studied under various conditions. The arylmethylation of DCN and DCA occurred in the photoreaction under nitrogen atmosphere, whereas the oxygenation of the arylmethyl organometallic compounds occurred in the photoreaction under oxygen atmosphere. Key intermediates in these reactions in acetonitrile were radical ions which were generated via photoinduced electron transfer from the arylmethyl organometallic compounds to the excited singlet of DCN or DCA. The cleavage of the carbon-metal bond of the radical cations of the arylmethyl compounds resulted in the formation of arylmethyl radicals. The radicals reacted then with the radical anions of DCN and DCA to produce the arylmethylated compounds or reacted with oxygen to produce the oxygenated compounds. The efficiency of the photoreactions was affected by solvents and added materials to the reaction systems. In the photoreactions in benzene, the exciplexes of the type 1[A-ArCH2MR3]* or the triplexes of the type [A-C6H6-ArCH2MR3]* (A=DCN, DCA) were involved as intermediates. The reactivity features of the photoreactions are discussed.
ON THE MECHANISM OF THE PHOTOCHEMICAL REACTION BETWEEN 1,4-NAPHTHALENEDICARBONITRILE AND METHYLBENZENES
Albini, Angelo,Fasani, Elisa,Sulpizio, Ada
, p. 3562 - 3566 (2007/10/02)
On the basis of the correlation between fluorescence quenching and reaction quantum yield and of deuteration studies, it is shown that the photochemical reaction between 1,4-naphthalenedicarbonitrile (NDN) and methylbenzenes involves (i) water-mediated proton transfer within the charge-transfer exciplex, (ii) in-cage reaction of the two radicals to form 2-benzyl-1,2-dihydro-1,4-naphthalenedicarbonitrile (2) and 6,11-dicyano-5,11-methano-5,6,11,12-tetrahydrodibenzocyclooctene (3), the formation of the latter product requiring a further water-mediated hydrogen transfer, and (iii) escape of the benzylic radical, which is trapped by NDN, to give 4-benzyl-1-naphthalenecarbonitrile (1), a product formed also when benzylic radicals are generated from other sources.
