π ‐Extended Silyl Enolates as Emerging Platforms in Radical Chemistry
Debora Guazzetti, Kelly Bugatti, Claudio Curti, Franca Zanardiπ ‐Extended silyl polyenol ethers and their related silyl ketene acetals are well‐established vinylogous nucleophiles in polar transformations; however, their potential in radical chemistry has only recently emerged. Owing to their intrinsically electron‐rich character, arising from conjugated π ‐systems and σ ‐donating silyl groups, these substrates display unique reactivity under single‐electron transfer conditions. This review provides a comprehensive overview of their behavior in radical‐mediated processes, highlighting their versatile role as electron‐rich SOMOphiles, radical precursors, and nucleophilic partners in radical–polar crossover manifolds. A key concept underlying their reactivity is the umpolung induced by single‐electron oxidation, which converts nucleophilic vinylogous enolates into electrophilic radical cation or keto‐allyl radical intermediates, thereby unlocking unconventional bond‐forming pathways inaccessible through traditional two‐electron chemistry. Moreover, these systems exhibit a distinctive propensity for remote functionalization at γ‐ , ε‐ , and η ‐positions, governed by electronic delocalization and radical stabilization across the extended π ‐framework. Recent advances in photoredox catalysis, electrochemistry, and transition metal‐mediated methodologies have significantly expanded the scope and synthetic utility of these transformations, enabling efficient C─C and C─heteroatom bond formation, enantioselective variants, and applications in the synthesis of complex molecules. Collectively, these developments position π ‐extended silyl polyenol ethers as versatile and tunable platforms in modern radical chemistry.