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DOI: 10.1055/s-0030-1258322
Palladium-Catalyzed Coupling Reaction of α-Diazocarbonyl Compounds with Aromatic Boronic Acids or Halides
Publication History
Received
6 September 2010
Publication Date:
15 November 2010 (online)


Abstract
Efficient palladium-catalyzed cross-coupling reactions of α-diazocarbonyl compounds and arylboronic acids or aryl halides have been developed. The reaction proceeds smoothly for a range of diazo compounds, boronic acids, and halides. The coupling reaction conditions tolerate various substituents on the aromatic rings of the substrates, such as chloro, fluoro, acyl, oxo, ester, and nitro groups. This coupling reaction constitutes a novel access to α-aryl-substituted α,β-unsaturated carbonyl compounds. Mechanistically, palladium-carbene is supposed to be the key intermediate; its formation is followed by migratory insertion of an aryl group to the carbenic carbon of the palladium-carbene complex and subsequent β-hydride elimination. Kinetic isotope effect (KIE) data measured for intra- and intermolecular competition experiments suggest that β-hydride elimination is not involved in the rate-determining step.
Key words
palladium catalysis - cross-coupling - diazo compounds - aryl halides - arylboronic acids