Letteratura scientifica selezionata sul tema "(cyclic) diaryl λ3-bromanes"

Here the example of the efficient construction of important dihydrobenzisoxazole cores from the cycloaddition reactions between cyclic diaryl λ3-bromanes as the aryne precursors and nitrones is reported. Many dihydrobenzisoxazole-containing compounds...

The homo anion-cation of cyclic diaryl λ3-bromanes/diarylbrominiums, which was not reported in previous reports, has been disclosed for the first time. The competitive experiments indicates that the anion-cation coupling is...

Despite the remarkable advancements in hypervalent iodine chemistry, exploration of bromine and chlorine analogues remains in its infancy due to their difficult synthesis. Herein, we introduce six‐membered cyclic λ3‐bromanes and λ3‐chloranes. Through single‐crystal X‐ray structural analyses and conformational studies, we delineate the crucial bonding patterns pivotal for the thermodynamic stability of these compounds. Notably, these investigations reveal pronounced π‐π stacking phenomena within the crystal lattice of hypercoordinated bromine(III) and chlorine(III) species. Their reactivity profile is explored as they are radical precursors or electrophilic reagents in metal‐free intermolecular biaryl couplings, O‐ and S‐arylations, and Cu(I)‐promoted intramolecular biaryl couplings which is complementary to the known reactivity of five‐membered bromanes and chloranes. Mechanistic insights are provided, elucidating the pathways governing their reactivity and underscoring the potential in organic synthesis.

Despite the remarkable advancements in hypervalent iodine chemistry, exploration of bromine and chlorine analogues remains in its infancy due to their difficult synthesis. Herein, we introduce six‐membered cyclic λ3‐bromanes and λ3‐chloranes. Through single‐crystal X‐ray structural analyses and conformational studies, we delineate the crucial bonding patterns pivotal for the thermodynamic stability of these compounds. Notably, these investigations reveal pronounced π‐π stacking phenomena within the crystal lattice of hypercoordinated bromine(III) and chlorine(III) species. Their reactivity profile is explored as they are radical precursors or electrophilic reagents in metal‐free intermolecular biaryl couplings, O‐ and S‐arylations, and Cu(I)‐promoted intramolecular biaryl couplings which is complementary to the known reactivity of five‐membered bromanes and chloranes. Mechanistic insights are provided, elucidating the pathways governing their reactivity and underscoring the potential in organic synthesis.

Regiodivergent reactions are a fascinating tool to rapidly access molecular diversity while using identical coupling partners. We have developed a new approach for regiodivergent synthesis using the dual character of hypervalent bromines. In addition to the recently reported reactivity of hypervalent bromines as aryne precursors, the first transition metal‐catalyzed reaction is reported. Accordingly, the development of these two complementary transformations allows for alteration of regioselectivity to furnish both ortho‐ and meta‐substituted alkynylation products. Mechanistic and computational studies show how these selectivities are controlled.

Regiodivergent reactions are a fascinating tool to rapidly access molecular diversity while using identical coupling partners. We have developed a new approach for regiodivergent synthesis using the dual character of hypervalent bromines. In addition to the recently reported reactivity of hypervalent bromines as aryne precursors, the first transition metal‐catalyzed reaction is reported. Accordingly, the development of these two complementary transformations allows for alteration of regioselectivity to furnish both ortho‐ and meta‐substituted alkynylation products. Mechanistic and computational studies show how these selectivities are controlled.

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