111359-34-3Relevant articles and documents
Remarkable kinetic stability of α-thiocarbamoyl substituted 4-methoxybenzyl cations
McClelland, Robert A.,Licence, Victoria E.,Richard, John P.,Williams, Kathleen B.,Lin, Shrong-Shi
, p. 1910 - 1915 (1998)
4-Methoxybenzyl cations bearing α-(N,N-dimethylcarbamoyl) and α-(N,N-dimethylthiocarbamoyl) substituents have been generated photochemically upon irradiation of precursors with pentafluorobenzoate or 4-methoxybenzoate leaving groups. The ions have been observed with flash photolysis in 40:60 acetonitrile:water and in 50:50 methanol:water, and rate constants were measured for their decay in solvent alone and for their capture by azide ion. The cations so studied and their lifetimes in 40% acetonitrile are 6, ArC+H-CONMe2, 0.6 μs; 2, ArC+H-CSNMe2, 7 ms; and 4, ArC+(CH3)-CSMe2 6 ms, where Ar = 4-MeOC6H4. The cation 4 reacts with solvent by elimination of a proton from the α-methyl group, and the rate constant for solvent addition must be less than 1 s-1. The CSNMe2 substituted cations are 105-107-fold longer lived than analogs where the thioamide group has been replaced with an α-methyl. The UV-visible absorption spectra of these two cations also show significant differences from those of typical 4-methoxybenzyl cations. Thus, both the lifetimes and spectra point to a strong interaction of the benzylic centre with the thioamide group.
DESTABILIZED CARBOCATIONS. NUCLEAR MATNETIC RESONANCE DETECTION AND REACTIVITIES OF ARYL α-THIOFORMAMIDYL CATIONS
Ablenas, F. J.,George, B. E.,Maleki, M.,Jain, R.,Hopkinson, A. C.,Lee-Ruff, E.
, p. 1800 - 1803 (2007/10/02)
A series of α-aryl and diarylthioformamidyl cations were observed by low-temperature nuclear magnetic resonance spectroscopy.These ions undergo efficient cyclization and deprotonation to give benzothiophenes.
