Unexpected reactivity of pyridinium salts toward alkynyl Fischer complexes to produce <i>oxo</i>‐heterocycles

Flores-Conde, María Inés; Cruz, Fabiola N. de la; López, Juan José Marín; Jiménez‐Halla, J. Óscar C.; Peña‐Cabrera, Eduardo; Flores‐Álamo, Marcos; Delgado, Francisco; Vázquez, Miguel Á.

doi:10.1002/aoc.4202

Cited by 5 publications

(2 citation statements)

References 57 publications

(36 reference statements)

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“…Therefore, investigating the behavior of Fischer carbenes in chemical reactions promoted by microwave energy is a relevant approach. In the methodologies developed by our group for the reaction of alkynyl and vinyl(alkoxy)carbene complexes under thermal conditions, substituents proved to play an important role in reactivity and selectivity during the synthesis of a variety of compounds, such as ortho-and para-quinones [39], phenols [12,40,41], furans, pyran-2-ones [42], 4-amino-1-azadienes [14], and pyrroles. The aim of the current contribution was to explore the reactivity of alkynyl(ethoxy)carbene complex 1 with benzylidene anilines 2a-p under microwave irradiation.…”

Section: Introductionmentioning

confidence: 99%

Microwave-Assisted Reactivity of a Fischer Alkynyl Carbene Complex with Benzylidene Anilines

Delgado Reyes,

Feliciano,

Vazquez

et al. 2024

J. Mex. Chem. Soc.

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The reaction between the Fischer carbene complex (CO)5Cr=C(OEt)CºCPh and various benzylidene anilines RCH=NR1 was promoted by microwave irradiation, generating stable cross-conjugated metallahexatrienes in 45-70 % yield. Compared to conventional heating, the present conditions provided shorter reaction times with moderate yields. The geometrical configuration and the most stable conformation for each of the Fischer carbene complexes and their oxidation products were established by NMR and DFT analysis. The reaction mechanism was explored by DFT calculations of the potential energy surface, suggesting a 1,4-addition/ring closure/electrocyclic opening cascade process. Resumen. Se reporta la reactividad entre el carbeno de Fischer (CO)5Cr=C(OEt)CºCPh y las bencilidén anilinas, RCH=NR1, empleando irradiación de microondas. Los resultados indican que el calentamiento por microondas generó metalohexatrienos cruzados estables en rendimientos de 45-70 %, mostrando además, que los nuevos complejos se obtienen en tiempos de reacción más cortos y rendimientos moderados en comparación con las condiciones de calentamiento convencional. La configuración geométrica y la conformación más estable para los complejos carbénicos de Fischer y de sus derivados oxidados fueron establecidos por medio de RMN y DFT. La exploración de la superficie de energía potencial por cálculos DFT mostró que el proceso consistió en una reacción en cascada incluyendo una secuencia de adición-1,4, cierre de anillo y apertura electrocíclica.

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Section: Introductionmentioning

confidence: 99%

Microwave-Assisted Reactivity of a Fischer Alkynyl Carbene Complex with Benzylidene Anilines

Delgado Reyes,

Feliciano,

Vazquez

et al. 2024

J. Mex. Chem. Soc.

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“…FCCs containing group VI transition metals [29,31–33] are very versatile in cyclization and cycloaddition reactions with an α,β‐unsaturated system under different conditions, [29] resulting in carbocycles, [34–39] heterocycles [29,40–43] and a diversity of other compounds. Chromium carbene complexes have shown particularly suitable reactivity, compared to the greater stability of tungsten and the extreme reactivity of molybdenum complexes [44–47] .…”

Section: Introductionmentioning

confidence: 99%

Fischer Carbene Complexes: A Glance at Two Decades of Research on Higher‐Order Cycloaddition Reactions

Feliciano

Vázquez

Benítez‐Puebla

et al. 2021

Chemistry A European J

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The structure of Fischer carbene complexes (FCCs) is electron deficient. If bearing an α,β‐unsaturated system, it can generate a wide variety of compounds by undergoing many different transformations, including higher‐order cycloadditions. The latter are described as pericyclic reactions in which more than six electrons participate. These reactions have been employed in various areas of organic synthesis, resulting in highly selective compounds with a broad range of scaffolds. The first studies on higher‐order cycloadditions involving FCCs frequently yielded competing byproducts. Many groups have attempted to increase selectivity by exploring distinct reaction conditions, reagents and co‐catalysts (e. g., metal‐mediated cycloadditions). The present review is the first to focus exclusively on using higher‐order cycloadditions involving FCCs to synthesize carbocycles and heterocycles. Based on two decades of reports, an analysis is made of the main aspects of the mechanisms proposed for higher‐order cycloadditions and the structural diversity obtained by the substituent effect.

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Metal-carbonyl promoted multicomponent coupling of alkynes for the synthesis of heterocyclic compounds

Mathur

Misra

2020

Advances in Organometallic Chemistry

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Unexpected reactivity of pyridinium salts toward alkynyl Fischer complexes to produce oxo‐heterocycles

Cited by 5 publications

References 57 publications

Microwave-Assisted Reactivity of a Fischer Alkynyl Carbene Complex with Benzylidene Anilines

Microwave-Assisted Reactivity of a Fischer Alkynyl Carbene Complex with Benzylidene Anilines

Fischer Carbene Complexes: A Glance at Two Decades of Research on Higher‐Order Cycloaddition Reactions

Metal-carbonyl promoted multicomponent coupling of alkynes for the synthesis of heterocyclic compounds

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