Palladium-catalyzed carbonylative annulation of o-alkynylphenols: syntheses of 2-substituted-3-aroyl-benzo[b]furans.
We report here a general synthetic methodology for palladium-catalyzed carbonylative annulation of o-alkynylphenol to construct 2-substituted-3-aroyl-benzo[b]furan. On the basis of the results, this methodology could be applied to a wider selection of iodide substrates to generate desired products. In accordance with mechanistic studies, this process involves coordination of cationic and less hindered acyl palladium complexes with o-alkynylphenols to create a desired cascade triad (coordination, nucleophilic addition, and reductive elimination). Consistent with this mechanism, addition of 1 equiv of AgBF(4) to palladium catalyst Pd(Ph(3)P)(4) generates an ideal candidate for this unique transformation.
Hu
Youhong
Y
Institute of Chemistry and Cell Biology, Harvard Medical School, Boston, Massachusetts 02115-5731, USA. zhen_yang@hms.harvard.edu
Zhang
Yan
Y
Yang
Zhen
Z
Fathi
Reza
R
D001572:Benzofurans / Q000138:chemical synthesis*; D002384:Catalysis; D002625:Chemistry, Organic / Q000379:methods; D002855:Chromatography, Thin Layer; D003500:Cyclization; D004951:Esterification; D006841:Hydrocarbons, Aromatic / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D015394:Molecular Structure; D010165:Palladium / Q000737:chemistry
D001572:Benzofurans; D006841:Hydrocarbons, Aromatic; D010165:Palladium