o-Benzenedisulfonimide as a recyclable cationic organocatalyst for the controlled/living ring-opening polymerization of δ-valerolactone and -caprolactoneElectronic supplementary information (ESI) available: Synthesis of o-benzenedisulfonimide; characterization data (1H, 13C NMR, and mass spectrometry) of o-benzenedisulfonimide and additional data and spectra. See DOI: 10.1039/c3py01613g

o -Benzenedisulfonimide (OBS) was demonstrated for the first time to be a safe, recyclable, and water-tolerant Brønsted acidic catalyst for the ring-opening polymerization (ROP) of δ-valerolactone and -caprolactone using benzyl alcohol as the initiator. The polymerizations proceeded to afford poly(δ-valerolactone) and poly( -caprolactone) with controlled molecular weights and narrow polydispersities. The kinetics and chain extension experiments were carried out to confirm the controlled/living fashion of the polymerizations. In addition, 1 H NMR and MALDI-TOF MS measurements strongly indicated that the initiator residue was incorporated into the obtained polymers. Furthermore, well-defined poly(δ-valerolactone)- block -poly( -caprolactone) has been successfully synthesized via OBS-catalyzed ROP. A safe, recyclable, and water-tolerant Brønsted acid o -benzenedisulfonimide (OBS) catalyzed ROP of lactones in a living/controlled manner.