- Phosphonation of Aryl Halides by Copper(I) Complexes of Trialkyl Phosphites
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The copper complexes 2> (1; R=Me or Et), (bpy)> (2; R=Me or Et) (bpy is 2,2'-bipyridine), and 2> react with certain 2-halogenoazobenzene compounds, ArX, at room temperature to form the corresponding dialkyl arylphosphonates, ArP(O)(OR)2, and the products, ArH and Ar2, of reductive substitution and biaryl coupling.The ester, MeCO2R, and a copper(I) halide complex (e.g. >) are also formed.Kinetic studies of the reactions of some of these copper complexes with 2'-acetamido-6-bromo-4'-diethylamino-2,4-dinitroazobenzene in alcohol solution show that the phosphonation reactions are equal concentration second-order processes in each case.The effects of a radical scavenger and of light on the reaction suggest the involvement of radicals in the formation of ArH and Ar2, but not in the formation of ArP(O)(OR)2.The effects of different substituents in ArX, of changes in solvent, and of various additives on these reactions are investigated.A mechanism involving concerted nucleophilic substitution within the coordination sphere of copper(I) is proposed.
- Connor, Joseph A.,Dubowski, Danuta,Jones, Anthony,Price, Raymond
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p. 1143 - 1148
(2007/10/02)
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- Process for the manufacture of aromatic phosphonates
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A process for the manufacture of aromatic phosphorus derivatives of the formula: where R is an optionally substituted alkyl, alkenyl, aralkyl, cycloalkyl or aryl radical, and Ar is an aromatic radical linked to the phosphorus atom through a carbon atom of the aromatic radical which comprises contacting a phosphorous acid diester of the formula: with an aromatic halide of the formula Ar--X in the presence of copper or a copper compound, the symbols R and Ar having the meanings stated above and X representing a halogen atom. The aromatic radical preferably contains an atom or group activating the halogen atom. The process provides an improved method for manufacture of the phosphonic acid diesters.
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