Palladium(II) catalyzed carbonylative dimerization of allenyl ketones: efficient synthesis of difuranylketones

Palladium(II) catalyzed carbonylation of 1,2-allenyl ketones 1 in the presence of p-benzoquinone (1 equiv) under a CO atmosphere (balloon) afforded difuranylketones 4 in moderate to good yields. Mechanistically, the electron-withdravving nature of the acyl group should enhance the electrophilicity of the acylpalladium species B, and thus promote the oxypalladation of an additional molecule of 1, leading to the difuranyl ketone 4. (C) 2009 Elsevier Ltd. All rights reserved.