The Organic Chemistry of Copper

Abstract

This chapter discusses the organic chemistry of copper. Organocopper compounds have been obtained by many methods; the one commonly employed is the metathetical reaction between an organometallic reagent, wherein the metal is higher than copper in the electromotive series, and a copper salt. A general method for the preparation of organocopper compounds of the type RCu is the reaction of a Grignard or lithium reagent with an excess of a copper salt. Organocopper compounds, such as methyl–, phenyl–, tolyl–, and ethynylcopper are easily isolated by the virtue of their insolubility in the media employed in their preparations. The structures of some copper compounds have been determined either by X–ray crystallography or by a combination of nuclear magnetic resonance (NMR) and mass spectroscopic data and the degree of association. Ultraviolet spectral data have been reported for a few organocopper compounds. Organocopper–isocyanide complexes are assumed to be intermediates in certain organic syntheses. Perfluoroalkylcopper and perfluoroarylcopper compounds are noticeably more thermally stable than the corresponding alkyl and aryl compounds. The thermal decomposition of aryl– and vinylcopper compounds is an alternative method of obtaining dimeric products from organocopper compounds. Organocopper compounds are useful reagents for coupling reactions with organic halides. A noticeable feature of the majority of reactions of diorganocuprates with alkyl halides is that the molar ratios of up to 5: 1, respectively, are employed for most effective coupling.