Certain Cu(I) and Cu(II) salts are able to mediate the dimerization of arylboronic acids in DMF. They provide the corresponding symmetrical biaryls in moderate to very good yields. It is possible to run the reaction catalytically under an oxygen atmosphere without a significant loss of yields.

The efficient generation of aryl radicals from arylboronic acids by manganese(III) acetate is described. In aromatic solvents, in situ generated aryl radicals afford the corresponding biaryls in very good yields. This method works selectively, and yields are better than those from similar, previously described methods. Arylboronic acids carrying sensitive functional groups also work efficiently.

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The reaction of phenylhydrazines with benzene in the presence of manganese() acetate affords biaryls in good yields. The same reaction was carried out with similar oxidants, such as Co III , Ce IV and Pb IV ; among these oxidants Mn III acetate shows higher efficiency and selectivity.

The first catalytic intermolecular aldehyde-ketone coupling via acyl phosphonate is reported. Acyl phosphonates are potent acyl anion precursors, which generate acyl anion equivalents under the influence of cyanide anion via phosphonate-phosphate rearrangement. These anions readily react with activated ketones to form acyloin type coupling in 41-95% yields.