Diastereoisomeric compounds as possible models for stereospecific polymerization

The stereoregular polymers of monoolefins arise from the polymerization of vinyl compounds, which do not have a symmetry plane perpendicular to the plane of the double bond. The generation of diastereoisomeric complexes when an olefin is coordinated to an asymmetric center is the first step of a polymerization process, leading to stereoregular polymers. When olefinic compounds with a symmetry lower than 2mm are coordinated to a transition metal in simple complexes, enantiomeric mixtures are obtained. The resolution of such a type of asymmetry was achieved via fractional crystallization of diastereoisomeric mixtures with an asymmetric ligand. The study of properties of cis and trans π‐complexes of the type [olefin‐Pt‐dichloro‐α‐phenethylamine] gave evidence that the formation of the cis complexes involves a remarkable asymmetric induction also in solution. Complexes of Fe(CO)4 with unsaturated carboxylic acids were also resolved.