Tetrahedron Letters p. 1257 - 1260 (1992)
Update date:2022-08-17
Topics:
Janzen, Edward G.
Hinton, Randall D.
Kotake, Yashige
α-Hydroxy-(3- and 4-substituted)-benzyl tert-butyl aminoxyl radicals, the hydroxyl radical spin adducts of 3- and 4-substituted α-phenyl N-tertbutyl nitrones (R-PBN's), decay rapidly (in seconds) by first order kinetics in acetonitrile (ACN).The Hammett equation is obeyed with p = -1.36 and r = 0.90.Polar solvents produce an increase in rate of decay: water (fast) > ACN (fast) > benzene (slow).Thus substantial charge separation in the transition state is indicated.The mechanism proposed is a unimolecular cleavage reaction producing the substituted benzaldehyde and tert-buty nitroso anion radical:
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