Alternating Sequence Controlled Copolymer Synthesis of α‑Hydroxy Acids via Syndioselective Ring-Opening Polymerization of O‑Carboxyanhydrides Using Zirconium/Hafnium Alkoxide Initiators

• Published in: Journal of the American Chemical Society 2017-08, Vol.139 (31), p.10723-10732
• Main Authors: Sun, Yangyang, Jia, Zhaowei, Chen, Changjuan, Cong, Yong, Mao, Xiaoyang, Wu, Jincai
• Format: Article
• Language: English
• ISSN: 0002-7863; 1520-5126
• DOI: 10.1021/jacs.7b04712

The ring-opening polymerization (ROP) of O-carboxyanhydrides (OCAs) can give diverse poly­(α-hydroxy acid)­s (PAHAs) with different functional groups because of easy modification of the side group of OCAs, which can extend applications of PAHAs widely. The stereoselective polymerization of O-carboxyanhydrides and further sequence controlled alternating copolymerization of OCAs were still big challenges until now for lack of suitable catalysts/initiators. In this work, a highly syndioselective ROP of OCAs system as the first stereoselective example in this area is reported using zirconium/hafnium alkoxides as initiators with the highest P r value up to 0.95. Furthermore, these initiators were successfully applied in the precisely alternating sequence controlled copolymerization of PheOCA and Tyr­(Bn)­OCA, and alternating copolymerization of LacOCA and PheOCA was also achieved.