Polymerizations of (R,S)-3,7-dimethyl-1-octene in the presence of heterogeneous or homogeneous isotactic specific catalysts give very similar products with a homopolymeric isotactic structure. The insertion of (R,S)-3,7-dimethyl-1-octene into the metal-CH3 bend (both heterogeneous and homogeneous catalysts) is highly stereospecific and stereoselective.