N-Heterocyclic carbenes for metal-free polymerization catalysis: an update

This mini-reviewis intended to serve as a concise introduction to polymerizations that are catalysed byN-heterocyclic carbenes. The content is structured according to accessiblemonomerfunctionalities and type ofpolymerization. Both major achievements as well as the latest developments in this rapidly evolving field are presented. A broad range of different types of monomers is covered in this way, including among others lactones, epoxides, anhydrides, acrylates, siloxanes and lactams. Special emphasis is put on mechanistic understanding and structure-activity relationships. (C) 2015 Society of Chemical Industry