Covalent Template-Directed Synthesis: A Powerful Tool for the Construction of Complex Molecules.

Template-directed synthesis has become a powerful methodology to access complex molecules. Noncovalent templating has been widely used in the last few decades, but less attention has been paid to covalent template-directed synthesis, despite the fact that this methodology was used for the first reported synthesis of a catenane. This review highlights the evolution of covalent templating over the last 60 years, thereby providing a toolbox for the design of efficient covalent templating processes. Covalent templating represents a useful synthetic tool for accessing complex molecules, and the examples described here include the synthesis of macrocycles, mechanically interlocked molecules, linear oligomers, polydisperse linear polymers, and cross-linked polymer networks.