Efficient synthesis of bibutenolide derivatives through oxidative dimeric cyclization-coupling reaction of 2,3-allenoic acids

[GRAPHICS] An oxidative coupling-dimerization reaction of 2,3-allenoic acids was observed to provide an efficient route to bibutenolide derivatives, which are not readily available. A, new system (PdCl2/Rl/air) for regeneration of the palladium(II) catalyst was also established.