The McMurry-reaction allows the coupling of two carbonyl groups under reductive conditions using low valent titanium forming an alkenylene group. The so formed double bond acts as a link between the repealing units. Several diketones were converted into unsaturated polymers by reductive coupling in different ethers as solvent. By this method it is possible to prepare different derivatives of new or already well-known polymer classes. As an exemple we describe here first results of the synthesis of some derivatives of the classes of polypropenylenes, polybutadienes, polypentenamers, polyhexenamers and polydodecenamers. Syntheses of such polymers via common polymerisation or ROMP succeeds only in few cases.