Ring‐opening polycondensations

Ring‐opening polycondensation is a novel synthetic strategy using heterocycles of any ring size having two reactive bonds as bifunctional monomers in step‐growth polymerizations. The first part of this article reviews previous publications. The previous studies mainly dealt with syntheses of polyesters from tin‐containing macrocycles including cyclic polylactones. These tin‐containing cyclic oligomers or polymers were easily obtained in two ways, either by ring‐closing polycondensation of dibutyltin compounds with preformed diols or by ring‐expansion polymerizations of lactones by means of cyclic tin‐initiators. The second part of this article presents new results which deal with ring‐opening polycondensations of silicon containing macrocycles derived from oligo(ethylene glycol)s. In these cases the chain growth proceeds by elimination of dimethyl dichlorosilane. In addition to syntheses of homopolyesters, copolycondensations with silylated or stanylenated monomers were studied. Finally, the thermodynamical aspects of ring‐opening polycondensations will be discussed.