Search

Functionalized, saturated nitrogen heterocycles form the core structures of many molecules that have an impact on our daily lives, including natural products and pharmaceuticals. An efficient and general method for the direct alpha-peroxidation of saturated nitrogen heterocycles is reported. Upon simple reaction with tert-butyl hydrogen peroxide in the presence of catalytic amounts of copper(II) chloride and 1,10-phenanthroline, a broad range of nitrogen heterocycles equipped with a 2-pyridyl directing group are readily peroxidized at room temperature to the corresponding stable hemiaminals with full regioselectivity. These hemiaminals were, moreover, shown to be remarkably efficient precursors of the corresponding iminium ions upon simple treatment with citric acid, enabling, overall, the introduction of a series of nucleophiles at the alpha position of the starting nitrogen heterocycles., SCOPUS: ar.j, info:eu-repo/semantics/published

La triple liaison carbone-carbone des alcynes est l’un des groupes fonctionnels les plus simples et anciens en chimie, ses réactions et transformations appartenant aux fondations de la chimie organique. En plus de son utilisation très développée en synthèse organique, la présence de cette fonction dans de nombreux produits naturels et molécules issues de divers domaines de la chimie comme la biochimie et la science des matériaux souligne son importance et sa polyvalence.Parmi toutes les classes d’alcynes, les alcynes hétérosubstitués représentent une classe particulièrement intéressante, la présence d’un hétéroatome sur la triple liaison menant à une forte polarisation de cette dernière et permettant d’effectuer des réactions hautement régio- et stéréo-sélectives souvent délicates au départ d’alcynes. C’est grâce à la mise au point de méthodes efficaces et générales pour leur préparation que l’utilisation en synthèse de ces composés a connu un essor fulgurant. Parmi toutes les voies de synthèse disponibles, l’utilisation d’acétylures de cuivre comme agents d’alcynylation pour la synthèse d’alcynes substitués par un atome d’azote ou de phosphore s’est révélée particulièrement efficace et facile à mettre en œuvre.Dans ce contexte, la première partie de ce travail s’est intéressée à l’étude de la chimiosélectivité de la réaction d’alcynylation de nucléophiles azotés et phosphorés par des acétylures de cuivre. Le but de cette étude est de mieux comprendre les paramètres influençant la réactivité des acétylures de cuivre vis-à-vis de divers nucléophiles et de développer un protocole visant à réaliser l’alcynylation sélective d’un nucléophile par rapport à un autre. Les analyses quantitatives ont été réalisées par RMN du 13C, méthode de choix pour l’analyse rapide et efficace de mélanges réactionnels complexes.Intéressés par le développement de nouvelles réactions basées sur la réactivité des acétylures de cuivre, nous nous sommes ensuite tournés vers l’étude de leur util, Doctorat en Sciences, info:eu-repo/semantics/nonPublished

An efficient, broadly applicable, operationally simple and divergent process for the transformation of imides into arange of carboxylic acid derivatives under mild conditions is reported. By simply using catalytic amounts of ytterbium(III) triflate asa Lewis acid promoter in the presence of alcohols, water, amines or N,O-dimethylhydroxylamine, a broad range of imides aresmoothly and readily converted to the corresponding esters, carboxylic acids, amides and Weinreb amides in good yields. This methodnotably enables an easy cleavage of oxazolidinone-based auxiliaries., SCOPUS: ar.j, info:eu-repo/semantics/published

Due to their combined stability and peculiar reactivity, ynamides have emerged as remarkably useful building blocks for chemical synthesis. The development of general and robust methods for their preparation resulted in a massive interest for their chemistry. This notably resulted in the development of incredibly efficient processes starting from these building blocks which also recently found various applications in medicinal chemistry and natural product synthesis. Our efforts and contributions to the chemistry of ynamides, for which we have developed several reactions both for their preparation and for their use in synthesis, are overviewed in this highlight review., SCOPUS: re.j, info:eu-repo/semantics/published

gamma-Trifluoromethylated allenamides were obtained in good to excellent yields through a base-induced isomerization from the corresponding protected trifluoromethylated propargylic amines. The method, which simply required the treatment of the starting propargylic amines with sodium hydroxide in THF, was found to be fairly general and tolerates various alkyl and aryl substituents on the nitrogen atom and a range of protecting groups. The reactivity of the gamma-trifluoromethylated allenamides was explored and they were found to be excellent substrates for radical- and gold(I)-catalysed cyclizations yielding to fluoroalkylated nitrogen heterocycles., info:eu-repo/semantics/published

This is not breaking news: copper acetylides, readily available polymeric rock-stable solids, have been known for more than a century to be unreactive species and piteous nucleophiles. This lack of reactivity actually makes them ideal alkyne transfer reagents that can be easily activated under mild oxidizing conditions. When treated with molecular oxygen in the presence of simple chelating nitrogen ligands such as TMEDA, phenanthroline or imidazole derivatives, they are smoothly oxidized to highly electrophilic species that formally behave like acetylenic carbocations and can therefore be used for the mild and practical alkynylation of a wide range of nitrogen, phosphorus and carbon nucleophiles., SCOPUS: ar.j, info:eu-repo/semantics/published

Two practical and complementary methods are reported for the synthesis of trifluoromethylated alkynes. The first one, a mix-and-stir process, is based on the oxidative trifluoromethylation of readily available and bench-stable copper acetylides while the second one, which displays a broad substrate scope and has several advantages over existing procedures, is based on the oxidative copper- catalyzed direct trifluoromethylation of terminal alkynes. Both reactions provide user-friendly processes for the synthesis of trifluoromethylated acetylenes which can be easily obtained from readily available starting materials., SCOPUS: ar.j, FLWNA, info:eu-repo/semantics/published

Copper acetylides, readily available reagents which are characterized by their lack of reactivity, can be simply activated by oxidation with oxygen in the presence of simple nitrogen ligands such as TMEDA or imidazole derivatives. Upon activation, these nucleophilic species undergo a formal umpolung and can transfer their alkyne subunit to a wide range of heteronucleophiles, including amides, oxazolidinones, imines, and dialkyl phosphites. This alkynylation, which provides one of the most practical entry to useful building blocks such as ynamides, ynimines, and alkynylphosphonates, proceeds under especially mild conditions and can be easily performed on a multigram scale., SCOPUS: ar.j, info:eu-repo/semantics/published

info:eu-repo/semantics/published

info:eu-repo/semantics/published