In 1955, G. Wilke and co-workers found a simple method to synthesize cyclododeca-l,5,9-triene (CDT) by the trimerization of butadiene with a Ziegler catalyst consisting of TiCI, and (C2H5)2.41CI. It is necessary to increase the Ti : Al atomic ratio to 1 :4- 1 : 5 as otherwise this catalyst (e.g., with a 1 : 1 ratio) would preferentially transform butadiene into 1,4-frans-poly- butadiene.