Versatility of radical coupling in construction of topological polymers

The development of various polymerization mechanisms has paved the way for the construction of well-defined polymers with complicated structures. However, a single polymerization mechanism or a simple combination of several mechanisms often cannot meet the requirements. Thus, some efficient coupling reactions would play an important role in polymer science. In this review, we focused on the application of radical coupling in the construction of topological polymers. The atom transfer radical coupling (ATRC) reaction and agent (such as styrene, nitrone or diene) assisted radical coupling proceeded in a homocoupling style and polymers with symmetrical structures were obtained. As a more versatile method, nitroxide radical coupling (NRC) was also discussed, which proceeded in a heterocoupling style and polymers with various asymmetrical structures could be designed. Finally, the prospects of radical based coupling reactions in polymer science were also suggested.