Topology-Reset Execution: Repeatable Postcyclization Recyclization of Cyclic Polymers

A Strategy toward Cyclic Topologies Based on the Dynamic Behavior of a Bis(hindered amino)disulfide Linker

A simple and efficient method to generate macrocyclic structures has been developed based on the dynamic behavior of the linker bis(2,2,6,6-tetramethylpiperidin-1-yl)disulfide (BiTEMPS). The prime linear structure was transformed into a (macro)cycle using the following sequence: 1) thiol-ene reaction with a BiTEMPS derivative to afford the linear precursor, then 2) an entropy-driven transformation induced by diluting and heating. The radicals generated from BiTEMPS upon heating are highly tolerant toward a variety of chemical species, including oxygen and olefins, but they exhibit high reactivity in exchange reactions, which can be applied to the topology transformation of various skeletons. The advantages of the present method, namely, its procedural simplicity and substrate versatility, are demonstrated by the gram-scale synthesis of cyclic compounds with low and relatively high molecular weight.