Efficient palladium(II) catalysis under air. Base-free oxidative heck reactions at room temperature or with microwave heating

J Org Chem. 2007 Oct 12;72(21):7957-62. doi: 10.1021/jo701434s. Epub 2007 Sep 21.

Abstract

Scope and limitations of the base-free oxidative Heck reaction with arylboronic acids have been explored. Under our conditions, the dmphen-palladium(II)-catalyzed arylation proceeded with air or p-benzoquinone as reoxidants of palladium(0). We found that ambient temperature and mild aerobic conditions allow for the use of substrates sensitive to palladium(II)-catalyzed oxidation. Oxidative Heck couplings, employing different arylboronic acids, were smoothly and regioselectively conducted with both electron-rich and electron-poor olefins, providing high yields even with disubstituted butyl methacrylate, sensitive acrolein, and a vinylboronate ester. Controlled microwave processing was used to reduce reaction times from hours to minutes both in small scale and in 50 mmol scale batch processes.

MeSH terms

  • Acrylates / chemistry*
  • Aerobiosis
  • Benzene Derivatives / chemistry*
  • Boronic Acids / chemistry*
  • Catalysis
  • Chemistry, Organic / methods*
  • Hot Temperature*
  • Microwaves*
  • Oxidation-Reduction
  • Palladium / chemistry*
  • Temperature

Substances

  • Acrylates
  • Benzene Derivatives
  • Boronic Acids
  • Palladium
  • n-butyl acrylate