1531-30-2Relevant academic research and scientific papers
SRN1 reactions of aryl halides with carbanions initiated by sodium amalgam in liquid ammonia
Austin, Eduardo,Ferrayoli, Carlos G.,Alonso, Ruben A.,Rossi, Roberto A.
, p. 4495 - 4502 (2007/10/02)
The reaction of 1-chloronaphthalene with acetone (2a) and acetophenone (2b) enolate ions was initiated by sodium amalgam [Na(Hg)] in liquid ammonia giving good yields of the substitution products 3a and 3b respectively. 2-Chloroquinoline and 2-chloropyridine gave good yields of substitution product with 2b, and moderate to good yields with 2a. 4-Bromobenzophenone and 2a gave 78% of the substitution product 5. With aryl halides whose radical anions fragment fast and consequently close to the Na(Hg) surface, such as bromobenzene and p-bromoanisole, only dehalogenation products were observed. However, when benzonitrile was used as a redox catalyst, about 50% of the substitution product 6 was obtained with p-bromoanisole and 2a. However, with the more reactive carbanionic nucleophile, such as anthrone anion 4, good yields of the substitution product 7 were obtained with bromobenzene. In all these reactions neither reduction of the aromatic moiety nor the ketone functionality was observed. It is therefore suggested that Na(Hg) amalgam initiates these SRN1 reactions.
Hydrogen Atom Transfer Oxidation of Primary and Secondary Alcoholates into Aldehydes and Ketones by Aromatic Halides in Liquid Ammonia. A New Electrochemically Induceable Reaction
Amatore, Christian,Badoz-Lambling, Janine,Bonnel-Huyghes, Claudine,Pinson, Jean,Saveant, Jean Michel,Thiebault, Andre
, p. 1979 - 1986 (2007/10/02)
It is possible to induce the oxidation of alcoholates into the corresponding carbonyl compounds by electrochemical reduction of aromatic halides in liquid ammonia, i.e., to electrochemically trigger the reaction ArX + >CH-O- -> ArH + >C=O + X-.H-Atom transfer from the acoholate to the aryl radical formed upon reduction of the aryl halide appears as the key step of the oxidation process.The ketyl anion radical thus formed can be oxidized into the parent carbonyl compound, remain electrochemically stable, or be reduced into the dianion depending upon the location of the two corresponding standard potentials toward the reduction potential of the aryl halide.Electricity consumption thus tends toward 0, 1, and 2 F/mol for the three cases, respectively.The reactions competing with H-atom transfer, thus lowering the efficiency of the electrochemical inducement of the oxidation process, are electron transfer to the aryl radical which occur at the electrode surface and/or in the solution.These will play the role of termination steps for the corresponding chain system involving homogeneous initiation of the reaction.The kinetic analysis of the competition between H-atom transfer and homogeneous or heterogeneous electron transfer allows a detailed investigation of the reaction mechanism by electrochemical techniques such as cyclic voltammetry.This also leads to the determination of the rate constants of H-atom transfer of the alcoholate-aryl radical couple.
