No capítulo 1 apresentamos uma síntese eficiente de compostos 5-organoteluro-1H- 1,2,3-triazóis realizada via reação de cicloadição [3+2] entre azidas orgânicas e alquinos substituídos com organotelúrio. Além disso, os 5-organoteluro-1H-1,2,3-triazóis foram funcionalizados na posição 5 do anel triazólico por reação de acoplamento cruzado de Sonogashira. A regioquímica dos produtos de cicloadição foram descritas com base em experimentos de RMN, cálculos teóricos e cristalografia de raio-x. Apresentamos uma proposta mecanística para a cicloadição mediada por cobre, baseada em experimentos de espectrometria de massas de alta resolução. No capítulo 2, investigamos a eficiência de reações one-pot com indol, cloreto de oxalila e diferentes nucleófilos para obtermos derivados do indol-3-glioxila em condições adequadas. Do mesmo modo, envolvendo a adição de azidas orgânicas, levando à síntese de indol-3-glioxil-1,2,3-triazóis, os produtos foram obtidos com rendimentos que variaram de 59 a 85%. / In chapter 1 we present an efficient synthesis of 5-organotelluro-1H-1,2,3-triazole compounds that was accomplished via the [3+2]-cycloaddition reaction of organoazides and organotelluro alkynes. Additionally, 5-organotelluro-1H-1,2,3-triazoles were readily functionalized at the 5-position via the Sonogashira cross-coupling reaction, leading to highly functionalised triazoles. The regiochemistry of the products was assessed by bidimensional NMR experiments, theoretical calculations and x-ray crystallography. We presented a mechanistic proposal for the cycloaddition mediated by copper, based on high resolution mass spectrometry experiments. In chapter 2 we investigated a general and efficient reaction of indole with oxalyl chloride and nucleophiles providing indole-3-glyoxyl derivatives which has been developed in mild conditions. In the same fashion, the other reaction involved the addition of organic azides leading to the synthesis of indole-3-glyoxyl-1,2,3-triazoles, which proceeds smoothly generating the products in moderate to high yields.

No capítulo 1 apresentamos uma síntese eficiente de compostos 5-organoteluro-1H- 1,2,3-triazóis realizada via reação de cicloadição [3+2] entre azidas orgânicas e alquinos substituídos com organotelúrio. Além disso, os 5-organoteluro-1H-1,2,3-triazóis foram funcionalizados na posição 5 do anel triazólico por reação de acoplamento cruzado de Sonogashira. A regioquímica dos produtos de cicloadição foram descritas com base em experimentos de RMN, cálculos teóricos e cristalografia de raio-x. Apresentamos uma proposta mecanística para a cicloadição mediada por cobre, baseada em experimentos de espectrometria de massas de alta resolução. No capítulo 2, investigamos a eficiência de reações one-pot com indol, cloreto de oxalila e diferentes nucleófilos para obtermos derivados do indol-3-glioxila em condições adequadas. Do mesmo modo, envolvendo a adição de azidas orgânicas, levando à síntese de indol-3-glioxil-1,2,3-triazóis, os produtos foram obtidos com rendimentos que variaram de 59 a 85%. / In chapter 1 we present an efficient synthesis of 5-organotelluro-1H-1,2,3-triazole compounds that was accomplished via the [3+2]-cycloaddition reaction of organoazides and organotelluro alkynes. Additionally, 5-organotelluro-1H-1,2,3-triazoles were readily functionalized at the 5-position via the Sonogashira cross-coupling reaction, leading to highly functionalised triazoles. The regiochemistry of the products was assessed by bidimensional NMR experiments, theoretical calculations and x-ray crystallography. We presented a mechanistic proposal for the cycloaddition mediated by copper, based on high resolution mass spectrometry experiments. In chapter 2 we investigated a general and efficient reaction of indole with oxalyl chloride and nucleophiles providing indole-3-glyoxyl derivatives which has been developed in mild conditions. In the same fashion, the other reaction involved the addition of organic azides leading to the synthesis of indole-3-glyoxyl-1,2,3-triazoles, which proceeds smoothly generating the products in moderate to high yields.

L’utilisation de matières premières renouvelables pour la production de produits chimiques est un enjeu majeur de l’industrie chimique. Elle vise à répondre aux contraintes environnementales et économiques de disponibilité des ressources fossiles et de limitation de l’empreinte carbone des produits chimiques. Il existe une famille de molécules fonctionnelles directement issues de la biomasse dénommées « molécules plateforme ». Parmi elles, le 5-hydroxyméthylfurfural (HMF), porteur d’une fonction aldéhyde, un motif furanique et un groupe CH2OH, est particulièrement intéressante. Cependant, sa stabilité modérée, notamment en conditions acides, est une forte limitation de sa chimie et son utilisation vers des cibles en chimie fine reste un défi. Les réactions multi-composantes conduisent à des architectures élaborées à partir de briques simples de manière économe en temps et nombre d’étapes. Beaucoup de ces réactions concernent la fonction aldéhyde, ce qui rend intéressant de les appliquer au 5-HMF. Ceci est l’objet de cette thèse, qui porte sur deux réactions en particulier, Biginelli et Kabachnik-Fields. La réaction de Biginelli est la condensation d’un aldéhyde, un composé dicarbonylé et une urée conduisant à des dihydropyrimidinones (DHPMs). Etant acido-catalysée, il a été nécessaire d’optimiser les conditions pour l’appliquer au HMF. Les meilleures conditions (réaction sans solvant, ZnCl2) ont permis d’atteindre une large variété de nouvelles DHPMs dans des rendements convenables à très bons. La réaction de Kabachnik-Fields est la condensation d’un aldéhyde avec une amine et un dialkyl phosphate, conduisant à des a-aminophosphonates. Les conditions optimales trouvées pour son application au 5-HMF sont l’utilisation d’iode comme catalyseur dans le solvant biosourcé 2-MeTHF à température ambiante ou modérément élevée. Une série de nouveaux a-aminophosphonates comportant le motif HMF a été préparé. Le groupe hydroxyméthyle issu du HMF persiste dans le produit, offrant de nombreuses possibilités de dérivation et démontrant son utilité comparativement à la chimie du furfural. / Recently, the production of chemicals, either bulk or fine chemicals, from renewable biomass has attracted growing interests due to the dwindling reserve of fossil resources and the increasing awareness of environmental concerns. Some chemicals with a structure able to generate a number of derivatives, and able to be directly produced from biomass, are referred to as bio-based “platform chemicals”, and constitute the bridge between biomass and down-stream chemicals. Among these chemicals, 5-hydroxymethylfurfural (HMF), bearing an aldehyde group, a hydroxymethyl group, and a furan moiety, is the most popular one. However, its limited stability obstructs its applications in organic synthesis. Thus, developing mild and efficient synthetic routes towards existing or novel fine chemicals from HMF is still a challenging task. Multicomponent reactions (MCRs) are powerful synthetic tools allowing the straightforward formation of elaborated molecules from simple starting materials in a time- and step-saving manner. Among MCRs, many involve the aldehyde as one of the reactive components, making HMF as a potential interesting substrate in such strategies. This thesis aims at exploring the use of HMF in MCRs to provide novel fine chemicals, focusing on two reactions, namely the Biginelli and Kabachnik-Fields reactions. The Biginelli reaction is a condensation of an aldehyde, a dicarbonyl compound and urea. Although it is an old reaction, it is still showing thriving vitality, as many of its products, namely dihydropyrimidinones, exhibit various biological properties. We have investigated the reaction by choosing proper conditions to adapt to HMF, notably with respect to acidic conditions. The best conditions found for the reaction are the use of ZnCl2 as a mild Lewis acid catalyst without any solvent, giving access to new dihydropyrimidinones in modest to good yields. The Kabachnik-Fields reaction is a one-pot condensation of aldehydes, amines and dialkyl phosphites, and is considered as the most efficient and convenient approach to a-aminophosphonates. For the specific case of HMF, we could establish that the best conditions were the use of iodine as a catalyst in the bio-based solvent 2-MeTHF and room or moderately elevated temperature. Using these optimized conditions, a wide range of HMF-based a-aminophosphonates were prepared in modest to excellent yields. The hydroxymethyl group persisting in HMF-based a-aminophosphonates offers the possibilities of further modification and derivatization, illustrating the benefit of HMF as compared to furfural, for accessing a wider scope of chemical structures.