Over the past decades, functional group manipulation of aromatic precursors has been a common strategy to access new aromatic compounds. However, these classical methods, such as Friedel-Crafts alkylations and electrophilic/nucleophilic aromatic substitutions, have shown lack of regioselectivity besides the use of activators in excess amounts. To this end, numerous benzannulations to form benzo-fused substrates via Diels-Alder (DA), ring-closing metathesis (RCM), cycloaddition, and transition-metal-promoted processes have been reported. Appending a benzene ring directly onto a pre-existing ring is preferable to many classical methods due to the likely reduction of reaction steps and superior regiocontrol. However, many of these benzannulation reactions require air- and/or moisture- sensitive reaction conditions, a last oxidation step, or the use of highly functionalized precursors. Here we disclose three ‘complementary’ intramolecular ring-opening benzannulations to access a large array of functionalized (hetero)aromatic scaffolds utilizing cyclopropenes-3,3-dicarbonyls, alkylidene cyclopropanes-1,1-diesters, and 2,3-dihydrofuran O,O- and N,O- acetals as building blocks. More than 70 benzo-fused aromatic compounds were synthesized using this complementary approach with yields up to 98% and low catalyst loadings. With these benzannulation reactions in hand, we aim to open the synthetic door to a handful of bioactive natural products.

Over the past decades, functional group manipulation of aromatic precursors has been a common strategy to access new aromatic compounds. However, these classical methods, such as Friedel-Crafts alkylations and electrophilic/nucleophilic aromatic substitutions, have shown lack of regioselectivity besides the use of activators in excess amounts. To this end, numerous benzannulations to form benzo-fused substrates via Diels-Alder (DA), ring-closing metathesis (RCM), cycloaddition, and transition-metal-promoted processes have been reported. Appending a benzene ring directly onto a pre-existing ring is preferable to many classical methods due to the likely reduction of reaction steps and superior regiocontrol. However, many of these benzannulation reactions require air- and/or moisture- sensitive reaction conditions, a last oxidation step, or the use of highly functionalized precursors. Here we disclose three ‘complementary’ intramolecular ring-opening benzannulations to access a large array of functionalized (hetero)aromatic scaffolds utilizing cyclopropenes-3,3-dicarbonyls, alkylidene cyclopropanes-1,1-diesters, and 2,3-dihydrofuran O,O- and N,O- acetals as building blocks. More than 70 benzo-fused aromatic compounds were synthesized using this complementary approach with yields up to 98% and low catalyst loadings. With these benzannulation reactions in hand, we aim to open the synthetic door to a handful of bioactive natural products.

The Bull-Hutchings-Quayle (BHQ) reaction is a novel method for the synthesis of 1-(bromo/chloro)napthalenes from 2-allyphenyl-2’,2’,2’-tri(bromo/chloro)acetates. The reaction is also known as Atom Transfer Radical Cyclisation-Benzannulation (ATRC-Benzannulation). The ATRC-Benzannulation of structurally diverse 2-(cyclohex-1-en-1-ylmethyl)phenyl 2’,2’,2’-trichloroacetates in the presence of 1,3bis-(2,6diisopropylphenyl)imidazolium copper(I) chloride [“Nolan NHC-CuCl”] complexes, using microwave or thermolytic methods, afford a range of 9-chloro-1,2,3,4-tetrahydroanthracenes. Efficient ATRC-Benzannulation has been restricted to microwave conditions so a thermolytic method has been developed as an alternative. Application of BHQ methodology toward the synthesis of the core structure of lactonamycin are reported. Stille, Suzuki and Sonogashira cross-coupling methods were used for the synthesis of diene precursors of a lactonamycin analogue. [4+2] Diels-Alder cycloadditions have been investigated with the diene precursors and various dienophiles. 1-Chloroquinone has been displaced with para-methoxyphenol to generate 1-para-methoxyquinone. CAN mediated oxidation of 1-para-methoxyquinone has yielded 1-hydroxyquinone.

Ce mémoire de thèse est composé de deux parties distinctes ayant comme thématique commune, les réactions de cycloisomérisation. Nous nous sommes intéressés dans un premier temps au développement d’une réaction tandem d’acétalisation / cycloisomérisation catalysée par des sels d’argents. Cette méthodologie nous a permis d’accéder sélectivement aux familles des furoquinoléines et des pyranoquinoléines. Ces composés ont été testés comme agents antipaludiques et ont donné des résultats prometteurs. Une gamme de dérivés de furoquinoléine a également donné des activités cytotoxiques intéressantes. L’étude de leur potentielle activité antitumorale s’inscrit dans le cadre d’un projet financé par la Ligue Nationale contre le Cancer. Une étude approfondie de la réaction tandem, nous a permis de mettre en évidence l’influence de composés azotés sur le comportement du sel d’argent. Cette caractéristique nous a conduits à catalyser nos réactions grâce à un complexe inusité jusqu’alors en catalyse organométallique : l’imidazolate d’argent. Dans un deuxieme temps, nous avons étudié une réaction de benzannélation catalysée par des sels de rhodium ou d’argent. La stratégie de synthèse implique des systèmes de type benzofurane, porteurs d’énynes fonctionnalisées par un éther d’énol silylé, et conduit à des dérivés de dibenzofuranes. Ces hétérocycles, connus pour être biologiquement actifs, présentent un intérêt particulier dans la chimie thérapeutique. Nous avons également travaillé sur des indoles et avons pu synthétiser des dérivés d’oxindole originaux / Among a variety of new synthetic transformations, transition-metal-catalyzed reactions are some of the most attractive methodologies for synthesizing heterocyclic compounds. In this context, two different cycloisomerization reactions are studied. We first developed an efficient and versatile access to pyranoquinoline and furoquinoline derivatives, thanks to a tandem silver-catalyzed acetalization /cycloisomerization reaction. The synthesized compounds presented interesting antimalarial activity when tested on a resistant strain of the parasite Plasmodium Falciparum. The antitumoral activity of some furoquinolines was also investigated within a project funded by the French National League Against Cancer. Interestingly, we noticed that the regioselectivity of the cyclization can be controlled depending on the type of silver catalyst used. The observed reaction regioselectivity, including also an interesting nitrogen effect, led us to develop a silver imidazolate polymer as a stable and new silver catalyst. We also described a rhodium-catalyzed benzannulation reaction of silyl-enol-ethers onto alkynes, leading to dibenzofurans derivatives. These heterocycles are well-known for their biological properties and their interest in therapeutic chemistry. Finally, we developed an original methodology for the synthesis of oxindole derivatives