Synthesis and crystal structure of CC(O)CH3>3>. Its role in the cyclotrimerization of 1-phenylbut-1-yn-3-one to 1,3,5-triphenyltris(carboxymethyl)benzene

Article abstract of DOI:10.1016/0022-328X(93)83075-7

The reaction of with 1-phenylbut-1-yn-3-one in refluxing toluene yields CC(O)CH3>>, the symmetrical trimer 3, which were characterized by spectroscopic techniques, and the title complex, the structure of which has been elucidated by X-ray analysis.The crystals are monoclinic P2₁/c with a = 10.640(2), b = 17.741(4), c = 17.845(4) Angstroem, β = 90.50(3) deg, Z = 4.The molecule has a Co-Co bond and the 3 chain links the cobalt atoms in a flyover arrangement.To our knowledge, this is the first example of stepwise formation of a symmetrical benzene from an asymmetrical, internal alkyne via this type of intermediate.