Palladium-mediated intramolecular carbonylative annulation of o-alkynylphenols to synthesize benzo[b]furo[3,4-d]furan-1-ones

[GRAPHICS] The carbonylative annulation of o-alkynylphenols mediated by PdCl2(PPh3)(2) and dppp in the presence of CsOAc at 55 degreesC in acetonitrile under a balloon pressure of CO generates functionalized benzo[b]furo[3,4-d]furan-1-ones in good yields. This novel synthetic approach provides a highly efficient method for diversification of the benzofuran scaffold for combinatorial synthesis.