‘Immortal’ anionic ring‐opening polymerization by metalloporphyrin catalyst

Ring‐opening polymerization of epoxide initiated by aluminium porphyrin gives polyether with narrow molecular weight distribution even in the presence of chain transfer agent such as alcohol. This is due to the rapid, reversible exchange between (porphinato)aluminium alkoxide as the growing species and alcohol. As a result, the growing polymer molecules never die, and the reaction may be called ‘immortal’ polymerization.