The mechanistic duality of (thio)urea organocatalysts for ring-opening polymerization
Date of Original Version
Among the various catalysts for ROP, H-bonding organocatalysts stand out in the precise level of reaction control they are able to render during ROP. The H-bonding class of organocatalysts are thought to effect ROP via dual activation of both monomer and chain end. (Thio)urea mediated ROP has experienced a renaissance as a new polymerization mechanism-mediated by imidate or thioimidate species-facilitates new modes of reactivity and new synthetic abilities. Indeed, the urea class of H-bond donors has been shown to be more active than their corresponding thioureas. The imidate mechanism remains highly active in polar solvents and exhibits remarkable control-and 'living' behavior-under solvent-free conditions, and a broad range of temperatures is accessible. The advancements in synthetic abilities have all evolved through a greater understanding of reaction mechanism. Through the continued synergistic advances of catalysis and material, the (thio)urea class of catalyst can find use in a host of potential applications, research and industrial environments.
Organic and Biomolecular Chemistry
Dharmaratne, Nayanthara U., Jinal U. Pothupitiya, and Matthew K. Kiesewetter. "The mechanistic duality of (thio)urea organocatalysts for ring-opening polymerization." Organic and Biomolecular Chemistry 17, 13 (2019): 3305-3313. doi:10.1039/c8ob03174f.