This thesis work is consecrated to the study of transition metal-catalyzed C-H activation processes for the synthesis or the functionalization of heterocycles. First, a new example of divergent catalysis was developed, which involves the employment of palladium tetrakis complex for the hydroamination or Pt(II) salts for the C-H hydroarylation reaction of O-propargyloxy anilines. The resulting benzopyranes are lately employed through a three steps efficient synthesis for the preparation of pyrano[3,2-h]quinolins. A new efficient version of Ru(0)-catalyzed carbonylative Murai reaction for the C3-H acylation was investigated using bidentate or aromatic imines as directing group. The coupling with vinylsilanes or styrenes was extended to a series of pentatomic heterocycles with moderate or excellent yields and the reaxtion mechanism was clarified by DFT calculation. Lastly, a totally new oxidant-free version of Ru(0)-catalyzed Fujiwara-Moritani reaction was studied. The trimeric complex of Ru3(CO)12 was employed for the C3-alkenylation with acrylates or electronpoor olefins with moderate or excellent yields. The reaction mechanism seems to proceed, after the activation step and the olefin insertion, through a -elimination step followed by a reductive elimination of the metal species formed.

Transition metal catalyzed cyclizations and C-H couplings of heterocyclic scaffolds / Roberto Sala , 2020. 33. ciclo, Anno Accademico 2019/2020.

Transition metal catalyzed cyclizations and C-H couplings of heterocyclic scaffolds

sala roberto
2020-01-01

Abstract

This thesis work is consecrated to the study of transition metal-catalyzed C-H activation processes for the synthesis or the functionalization of heterocycles. First, a new example of divergent catalysis was developed, which involves the employment of palladium tetrakis complex for the hydroamination or Pt(II) salts for the C-H hydroarylation reaction of O-propargyloxy anilines. The resulting benzopyranes are lately employed through a three steps efficient synthesis for the preparation of pyrano[3,2-h]quinolins. A new efficient version of Ru(0)-catalyzed carbonylative Murai reaction for the C3-H acylation was investigated using bidentate or aromatic imines as directing group. The coupling with vinylsilanes or styrenes was extended to a series of pentatomic heterocycles with moderate or excellent yields and the reaxtion mechanism was clarified by DFT calculation. Lastly, a totally new oxidant-free version of Ru(0)-catalyzed Fujiwara-Moritani reaction was studied. The trimeric complex of Ru3(CO)12 was employed for the C3-alkenylation with acrylates or electronpoor olefins with moderate or excellent yields. The reaction mechanism seems to proceed, after the activation step and the olefin insertion, through a -elimination step followed by a reductive elimination of the metal species formed.
2020
Ce travail de thèse est consacré à l'étude des processus d'activation C-H catalysés par les métaux de transition pour la synthèse ou la fonctionnalisation d'hétérocycles. Tout d'abord, un nouvel exemple de catalyse divergente a été développé, qui implique l'utilisation du complexe tétrakis de palladium pour l'hydroamination ou des sels de Pt(II) pour la réaction d'hydroarylation C-H des O-propargyloxy anilines. Les benzopyranes résultants sont récemment employés à travers une synthèse efficace en trois étapes pour la préparation de pyrano [3,2-h] quinolines.Une nouvelle version efficace de la réaction carbonylative de Murai catalysée par Ru(0) pour l'acylation C3-H a été étudiée en utilisant des imines bidentées ou aromatiques comme groupe directeur. Le couplage avec des vinylsilanes ou des styrènes a été étendu à une série d'hétérocycles pentatomiques avec des rendements modérés ou excellents et le mécanisme de réextion a été clarifié par calcul DFT.Enfin, une toute nouvelle version sans oxydant de la réaction Fujiwara-Moritani catalysée par Ru(0) a été étudiée. Le complexe trimérique de Ru3(CO)12a été utilisé pour l'alcénylation en C3 avec des acrylates ou des oléfines pauvres en électrons avec des rendements modérés ou excellents. Le mécanisme de réaction semble se dérouler, après l'étape d'activation et l'insertion d'oléfine, par une étape de -élimination suivie d'une élimination réductrice de l'espèce métallique formée.
Ruthenium; Transition Metals; Catalysis; Heterocycles; Hydroamination; Hydroarylation; Murai; Fujiwara-Moritani
Ruthénium; Métaux de transition; Catalyse; Hétérocycles; Hydroamination; Hydroarylation; Murai; Fujiwara-Moritani.
Transition metal catalyzed cyclizations and C-H couplings of heterocyclic scaffolds / Roberto Sala , 2020. 33. ciclo, Anno Accademico 2019/2020.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11383/2115625
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