Reaction of aromatic aldehydes and ketones with ytterbium metal gives the corresponding pinacols in high yields. Cross-coupling reaction of benzophenone with other carbonyl compounds to produce unsymmetrical pinacols is also described.
In the presence of Yb metal, diaryl ketones react nucleophilically with octan-2-one, acetonitrile, epoxides, and CO2 to give the corresponding unsymmetrical pinacols, α-hydroxy ketones, 1,3-diols, and α-hydroxy carboxylic acids, respectively.