| Popis: |
The reactivity of pure isolated copper(I) 2-halobenzoates has been studied at 20 and 80 °C either with or without oxidizing agents (O2 and CuBr2). Furthermore, these complexes have been reacted at 80°C either alone or in combination with sodium acetylacetonate, i.e. under “Hurtley reaction conditions”. Corresponding reactivity of the mixed (2-halobenzoato)(mesityl)copper(I) clusters, wherein the mesityl fragment can be considered as an intramolecularly bonded nucleophile, has also been studied. The organic products of these reactions and their distribution, measured by combined gas chromatography-mass spectrometry (GC–MS) and gas–liquid chromatography (GLC), for both types of reactions showed remarkable similarities. The principal products of these reactions, e.g. biaryls, methyl 2-(1-acetyl-2-oxopropyl)benzoate and 2-mesitylbenzoate derivatives, are formed by a halogen substitution reaction. Compared to the chlorobenzoate derivatives, the more reactive bromo species generate more by-products. The presence of a coordinating solvent, such as acetylacetone, proved to be necessary in order to obtain a good yield from the condensation reaction between the copper(I) 2-halobenzoates and sodium acetylacetonate. A detailed mechanism involving dinuclear copper(I) intermediates is proposed for the Hurtley reaction. |
