4165-80-4Relevant articles and documents
Homogeneous Rate Constants for Coupling between Electrochemically Generated Aromatic Anion Radicals and Alkyl Radicals
Pedersen, Steen U.,Lund, Torben
, p. 397 - 402 (2007/10/02)
Rate constants have been measured for the coupling between hexenyl radicals and 2,2-dimethylhexenyl radicals and electrogenerated anion radicals of anthracene, 9,10-diphenylanthracene, benzophenone and quinoxaline.The rate constant for all four reactions in N,N-dimethylformamide is log k2 = 9.1(5), which is in accordance previous results in 1,2-dimethoxyethane for naphthalene and benzophenone anion radicals and 1-hexenyl radicals.The data indicate that the redox potential of the aromatic anion radical has only a minor influence on the rate of coupling with alkyl radicals.The rate constants for anion radicals of 9,10-diphenylanthracene and benzophenone were somewhat lower, 6(1) x 108 M-1 s-1, which for 9,10-diphenylanthracene might be caused by steric hindrance by the two phenyl groups.The conclusion is that the coupling reaction between aromatic anion radicals and alkyl radicals has all the characteristics of a radical-radical coupling.
Organometallic Reaction Mechanisms. 17. Nature of Alkyl Transfer in Reactions of Grignard Reagents with Ketones. Evidence for Radical Intermediates in the Formation of 1,2-Addition Product Involving Tertiary and Primary Grignard Reagents
Ashby, E. C.,Bowers, Joseph R.
, p. 2242 - 2250 (2007/10/02)
When a Grignard reagent reacts with an aromatic ketone, a radical anion-radical cation pair is formed which can collapse to give 1,2-addition product or dissociate to form a radical anion and a free radical within the solvent cage which in turn can collapse to 1,2-addition product or a conjugate addition product or escape the solvent cage to form pinacol.The 1,2-addition products, which form after dissociation of the radical anion-radical cation pair, show free-radical character as indicated by the cyclized 1,2-addition products formed from the reaction of a tertiary Grignard reagent probe with benzophenone in THF and from the reaction of a primary Grignard reagent probe (neooctenyl Grignard reagent) with benzophenone in ether.The 1,6-addition products, which come about after dissociation of the radical anion-radical cation pair, show free-radical character as evidenced by the cyclized 1,6-addition products formed in all of the reactions which involve the tertiary probe Grignard reagent (in all solvents studied) with benzophenone and 2-MBP and also in the reaction of the neooctenyl probe Grignard reagent with 2-MBP.
