Single-electron and two-electron transfer in the anionic polymerization of vinyl monomers and the ring-opening polymerization of lactones

Single‐electron‐transfer (SET) and two‐electron‐transfer reactions and their mechanisms were examined in the anionic polymerization of vinyl monomers and in the ring‐opening polymerization of lactones. SET resulted in the formation of radical anions or enolates at the initiation step of styrene or lactone polymerization with naphthalene sodium as a catalyst. However, alkali‐metal supramolecular complexes such as M+crown–M− (M = Na or K) were able to transfer two electrons to both these monomers to form carbanions as reactive intermediates. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 2158–2165, 2002 Single‐electron‐transfer and two‐electron‐transfer reactions at the initiation steps of the anionic polymerizations of styrene and lactones were investigated. Naphthalene sodium and potassium, able to transfer single electrons, were used as active catalysts in the polymerization of styrene, for example, as were several alkali‐metal supramolecular complexes capable of two‐electron transfer.