Debora Guazzetti

π ‐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.

γ‐Butenolides are widespread structural motifs found in many natural and unnatural products which display an impressive range of biological activities. Among them, ε‐keto‐γ‐butenolides represent underestimated butenolide frameworks, which could serve as valuable platforms to build complex structures, for example, heterobicyclic derivatives. Quite unexpectedly, despite the apparent simplicity of their structures, efficient synthetic methodologies enabling the construction of chiral, ε‐keto‐γ‐butenolide architectures are quite underdeveloped. In this context, herein we present a novel, photoinduced regio‐ and chemoselective γ‐alkylation of 2‐silyloxyfurans with 2‐bromoketones providing a practical access to ε‐ketobutenolide scaffolds in racemic format, in one single step and high yields. The usefulness of these products as starting materials to build chiral, fused‐heterobicycle lactone derivatives was demonstrated by the implementation of a two‐step strategy which successfully delivered unprecedented phenyltetrahydrofuro[3,2‐ b ]furan‐2(3 H )‐one and tetrahydrofuro[3,2‐ c ]pyridazin‐6(1 H )‐one chemotypes.

Organocatalytic asymmetric transformation of common aromatic heterocycles via in situ formation of highly reactive dearomatized ortho‐quinodimethane diene species and subsequent [4+2] cycloaddition with suitable dienophiles has become a powerful tool to enter cyclohexane‐fused heterocycles. Most of these reactions were previously applied to benzo‐fused heterocycles or poorly aromatic rings. Herein, we disclose how previously intractable aromatic imidazole rings, equipped with removable methylidene malononitrile activating handle, could be involved as competent cycloaddends with β‐aryl enals in efficient eliminative [4+2] cycloadditions under mild organocatalytic conditions. This method allowed the efficient and direct preparation of scantly represented 6,7‐dihydrobenzo[d]imidazoles with optimal enantio‐ and regioselectivities. Post‐cycloaddition chemical editing provided imidazole‐based ring systems with diverse oxidation state and functional groups.