Letteratura scientifica selezionata sul tema "Silacyclic molecules"

AbstractSila-molecules have recently attracted attention due to their promising applications in medical and industrial fields. Compared with all-carbon parent compounds, the different covalent radius and electronegativity of silicon from carbon generally endow the corresponding sila-analogs with unique biological activity and physicochemical properties. Vinylsilanes feature both silyl-hyperconjugation effect and versatile reactivities, developing vinylsilane-based Smiles rearrangement will therefore provide an efficient platform to assemble complex silacycles. Here we report a practical Ir(III)-catalyzed cycloaromatization of ortho-alkynylaryl vinylsilanes with arylsulfonyl azides for delivering naphthyl-fused benzosiloles under visible-light photoredox conditions. The combination of experiments and density functional theory (DFT) energy profiles reveals the reaction mechanism involving α-silyl radical Smiles rearrangement.

AbstractC − Si Bond cleavage is one of the key elemental steps for a wide variety of silicon-based transformations. However, the cleavage of unstrained Si−C(sp3) bonds catalyzed by transition metal are still in their infancy. They generally involve the insertion of a M − C(sp2) species into the C − Si bond and consequent intramolecular C(sp2)‒Si coupling to exclusively produce siloles. Here we report the Pd-catalyzed sila-spirocyclization, in which the Si−C(sp3) bond is activated by the insertion of a M − C(sp3) species and followed by the formation of a new C(sp3)‒Si bond, allowing the construction of diverse spirosilacycles. This reactivity mode, which is strongly supported by DFT calculations may open an avenue for the Si−C(sp3) bond cleavage and silacycle synthesis.

Contrairement aux λ3-iodanes diaryliques bien étudiés, la chimie des dérivés λ3-bromane et λ3-chlorane a été rarement explorée en raison de leur synthèse complexe, occultant ainsi les applications potentielles. Nous nous sommes concentrés sur le développement de méthodes de synthèse efficaces pour les λ3-bromanes/chloranes (cyliques) diaryliques, ainsi que sur l'exploration de leur potentiel unique en tant que précurseurs d'arynes novateurs et leur réactivité en tant que réactifs efficace d’arylation. Les intermédiaires aryne, générés à partir de λ3-bromanes/chloranes, ont servi de plateformes synthétiques puissantes et durables pour la construction efficace de structures moléculaires complexes. De plus, l’insertion d'arynes dans les liaisons σ N–Si d’aminosilanes avec des réactifs λ3-bromanes/chloranes (cyliques) diaryliques a permis un accès direct à des dérivés 3-amino-2-silylbiaryls. Des investigations expérimentales mécanistiques, combinées à des calculs DFT, ont été menées pour élucider la réactivité distincte et améliorée des réactifs (cyliques) diaryliques de brome(III) et de chlore(III) dans transformations chimiques
In contrast to well-studied diaryl λ3-iodanes, the chemistry of λ3-bromane and λ3-chlorane congeners has been scarcely explored due to their challenging synthesis, shadowing their potential applications. For this purpose, we focused on developing the practical and efficient synthetic methods for (cyclic) diaryl λ3-bromanes/chloranes, as well as exploring their unique as novel aryne precursors and superior reactivity as enhanced arylating reagents. The aryne intermediates, generated from (cyclic) diaryl λ3-bromanes/chloranes, served as a potent and sustainable synthetic platforms for a straightforward and efficient construction of complex molecular frameworks. In addition, aryne insertion into N–Si σ-bonds of aminosilanes with cyclic diaryl λ3-bromane/chlorane reagents enabled a direct access to 3-amino-2-silylbiaryl derivatives. Experimental mechanistic investigations, combined with DFT calculations, were further conducted to elucidate the distinct and enhanced reactivity of the rarely explored (cyclic) diaryl hypervalent bromine(III) and chlorine(III) reagents in diverse and versatile chemical transformations