Arylation of alkenylidenecyclopropanes via Heck reaction. A simple access to arylallylidenecyclopropanes

Five alkenylidenecyclopropanes have been arylated using a catalytic amount of [Pd(C3H5)Cl]2 (0.004%) associated to the tetradentate ligand cis, cis, cis-1,2,3,4-tetrakis(diphenylphosphinomethyl)cyclopentane or Tedicyp as the catalyst. The carbo-palladation step occurs on the terminal double bond of the vinylidenecyclopropanes, without interaction with the internal one. The addition of the complex PdArL2 corresponds to an electrophilic attack on the face of the double bond, syn to the best electron-donor cyclopropyl substituent.