The Use of 5-Exo- and 6-Exo-trig Cyclizations in the Manipulation and Degradation of Biotic and Abiotic Polymers.

This JOCSynopsis underscores the pivotal role of 5-exo-trig and 6-exo-trig cyclization pathways in directing ring-closure reactions, with a focus on their application to the modification of biotic polymers, including amino acid labeling and N-terminal capping strategies in peptide stapling. This work extends these cyclizations to the degradation of both abiotic and biotic polymers. It also explores instances where degradation occurs through less favorable cyclization pathways, highlighting the complexity and context-dependence of these transformations. Additionally, it showcases the use of 5-exo-trig cyclization in reversible click chemistry, emphasizing its role in the design of dynamic materials. These insights are exemplified by systems such as a Meldrum's acid-derived conjugate acceptor, which can undergo reversible "click" and "declick" processes, paving the way for the development of polymers with tunable and responsive properties.