Advancements in thiol-yne click chemistry: Recent trends and applications in polymer synthesis and functionalization

The 2022 Nobel Prize in chemistry brought the world's attention to click chemistry, a field as fascinating as its name, characterized by attractive features like high yield, stereospecificity, and broad scope. Since its inception, click chemistry has been synonymous with copper-catalyzed azide-alkyne reactions, owing to their remarkable advantages. However, as the field advanced, there has been a proactive search to develop metal-free alternatives for more biocompatible applications. This led to the extensive adoption of thiol-ene click reactions in the past decade. Yet, due to the growing requirement for polymers with complex architecture and functionality, in recent years, thiol-yne click reactions have come to the forefront with additional advantages over its ene counterparts, allowing the addition of two thiols to an alkyne. This review provides a concise overview of some of the significant developments in polymer synthesis and functionalization utilizing thiol-yne click chemistry. The focus is primarily on radical-mediated thiol-yne reactions, considering the substantial body of work in this area. Moreover, the review provides adequate discussion on other mechanistic pathways like nucleophilic and metal-catalyzed thiol-yne reactions that have gained traction recently.