Academic literature on the topic 'Decarboxylative arylation'

Copper mediated decarboxylative direct C–H arylation of 5-membered heteroarenes with aryl carboxylic acids is developed using the molecular oxygen as sole oxidant. Copper plays the dual role in decarboxylation and C–H arylation.

Palladium-catalyzed decarboxylative arylation is reported using pyrroles N-protected with the 2-(trimethylsilyl)ethoxymethyl (SEM) group and featuring 2-, 3-, and 4-substituents about the pyrrolic framework. In contrast to N-protected pyrroles previously used in decarboxylative arylation, the use of SEM allows deprotection under mild conditions.

Aromatic rings are privileged structures found in a diverse range of natural and synthetic compounds, thus synthetic methods for their functionalisations are important in organic synthesis. Despite significant advancements made, especially in the field of transition metal catalysis, work still continues for the development of milder, more efficient, and more atom economical reactions. We describe here our efforts towards the development of decarboxylative/direct C(aryl)–N and C(aryl)–C bond forming reactions using aromatic carboxylic acids and unfunctionalised arenes as cheap and widely available aromatic sources. The investigations into copper-catalysed and copper/palladium-catalysed intermolecular and copper/silver/palladium-catalysed intramolecular decarboxylative amination of aromatic carboxylic acids are reported. A new approach to decarboxylation of benzoic acids is also described. The reaction uses silver (I) catalyst and peroxydisulfate salt to generate aryl radicals via oxidative decarboxylation. The applications of this approach in intra- and intermolecular decarboxylative C–H arylation, and protodecarboxylation are described. Also described is the development of silver-catalysed trifluoromethylation of simple arenes and heteroarenes. The reaction proceeds via radical trifluoromethylation using trimethyl(trifluoromethyl)silane as the trifluoromethyl radical source. This method has been applied to the trifluoromethylation of complex agrochemical molecules, proving its synthetic utility in late-stage functionalisation. Furthermore, we describe the exploitation of trifluoroacetate derivatives as cheap trifluoromethylating reagents in copper-mediated decarboxylative C–H trifluoromethylation of 2-phenylpyridine.

A ce jour, l’un des défis dans le développement des couplages directs catalytiques de type [C-H / C-CO2H] et [C-H / C-H] est de fonctionnaliser des briques moléculaires à haute valeur ajoutée synthétique possédant un haut potentiel d’aménagement dans le but d’accroître la diversité structurelle et fonctionnelle. Les éthers d’énols font partis de cette classe de motif structuraux ; cependant un déficit de méthodes de fonctionnalisation économiques en termes d’étapes, faciles à mettre en oeuvre et permettant de contrôler la régiosélectivité (α/β) et la stéréochimie (E/Z) de ces derniers est clairement observé. Ce travail de thèse s’inscrit dans ce contexte et a pour objectif de développer de nouvelles méthodes d’(hétéro)arylations régio- et stéréosélectives des α-carboxyvinyl éthers par couplages directs déshydrogénants [C-H / C-H] et décarboxylants [C-H / C-CO2H] impliquant deux partenaires de couplage inédits, les acides α-alkoxycinnamiques et les α-étheroxyacrylates d’éthyle. Ainsi, un premier chapitre a porté sur le développement d’une première méthodologie de préparation d’éthers d’énol gem-hétéroarylés basée sur l’engagement d’acides cinnamiques α-alkoxylés dans le couplage direct de type [C–CO2H / C–H] sous catalyse coopérative Pd(0) / Cu(I). Cette méthodologie a ensuite permis d’accéder aux 2-cétohétéroarènes α-énolisables après modulation de la fonction éther d’énol, et ces derniers ont ensuite été valorisés pour conduire aux systèmes 2,4’-bis-azoliques présents dans les polypeptides naturels. Les deux autres chapitres, deux et trois, ont été consacrés à l’étude de la fonctionnalisation de la position β d’éthers d’énol par couplages direct régio- et stéréosélectif pallado-catalysés des α-étheroxyacrylates d’éthyle selon deux stratégies : (1) Le couplage de Heck oxydatif décarboxylants de Myers de type [C-H / C-CO2H] avec les dérivés d’acides benzoïques et (2) le couplage oxydatif de Fujiwara-Moritani de type [C-H / C-H]
To date, one of the challenges in the development of catalytic direct couplings of [CH / C-CO2H] and [CH / CH] type is the functionalization of molecules, with high synthetic value, having a high potential of development in the goal of increasing structural and functional diversity. Enol ethers are part of this class of structural motifs; however, till now, no economical and selective functionalization method have been developed. In this context, the aim of this work was to develop a selective (hetero)arylation strategy of α-carboxyvinyl ether by direct dehydrogenative CH/ CH or decarboxylative C-H / C-CO2H cross coupling using α-alkoxy cinnamics acid and α-etheroxyacrylates as coupling partners. The first chapter has been focused on the development of the first methodology for the preparation of gem-heteroaryl enol ethers based on the engagement of α-alkoxylated cinnamic acids in the direct coupling of [C-CO2H / C-H] type under cooperative Pd(0) / Cu(I) catalysis. This methodology gave access to the α-enolizable 2-ketoheteroarenes after modulation of the enol ether function, and these were then valorized to give the 2,4'-bis-azole systems that are present in the natural polypeptides. The second and third chapters have focused on the study of β-functionalization of enol ethers by direct and selective Pd-catalyzed coupling of ethyl α-etheroxyacrylates according to two strategies: (1) Myers’s type decarboxylative Heck coupling [C-H / C-CO2H] with benzoic acid derivative and (2) Fujiwara-Moritani’s type [C-H / C-H] oxidative coupling