Rhodium-Catalyzed Crossed [2+2+2] Cycloaddition with Ynamides: Key-Strategy for the Concise Total Synthesis of 3-Oxygenated Carbazole Alkaloids

International audienceTotal syntheses of a set of naturally occurring 3-oxygenated carbazole alkaloids - 6-chlorohyellazole, carazostatin, carbazomycins A and B - are described. The key-strategy underlines a highly chemo- and regioselective rhodium-catalyzed [2+2+2] cyclotrimerization between appropriately tailored yne-ynamides and 1-methoxypropyne that is stirred by the interplay of stereoelectronic and steric effects allowing the introduction of four ring substituents of the natural carbazoles within a single step and making the overall syntheses short and efficient

Copper-Catalyzed Formation of C-P Bonds with Aryl Halides

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Copper-Catalyzed Formation of C-P Bonds with Aryl Halides

International audienc

1,3-Butadiynamides the Ethynylogous Ynamides: Synthesis, Properties and Applications in Heterocyclic Chemistry

International audience1,3-Butadiynamides-the ethynylogous variants of ynamides-receive considerable attention as precursors of complex molecular scaffolds for organic and heterocyclic chemistry. The synthetic potential of these C4-building blocks reveals itself in sophisticated transition-metal catalyzed annulation reactions and in metal-free or silver-mediated HDDA (Hexa-dehydro-Diels-Alder) cycloadditions. 1,3-Butadiynamides also gain significance as optoelectronic materials and in less explored views on their unique helical twisted frontier molecular orbitals (Hel-FMOs). The present account summarizes different methodologies for the synthesis of 1,3-butadiynamides followed by the description of their molecular structure and electronic properties. Finally, the surprisingly rich chemistry of 1,3-butadiynamides as versatile C4-building blocks in heterocyclic chemistry is reviewed by compiling their exciting reactivity, specificity and opportunities for organic synthesis. Besides chemical transformations and use in synthesis, a focus is set on the mechanistic understanding of the chemistry of 1,3-butadiynamides-suggesting that 1,3-butadiynamides are not just simple alkynes. These ethynylogous variants of ynamides have their own molecular character and chemical reactivity and reflect a new class of remarkably useful compounds

Catalyses au Cuivre et au Fer (Outils Efficaces pour la Formation de Liaisons C-P)

Cette thèse a été consacrée à la mise au point de nouveaux systèmes catalytiques peu toxiques, peu polluants et peu coûteux permettant la formation de liaisons C-P. Tout d abord, une nouvelle méthode de synthèse générale et efficace de butadiénylphosphines basée sur une réaction de couplage C-P catalysée au cuivre entre des bromobutadiènes fonctionnalisés et des phosphines secondaires (diaryle, dialkyle et alkylaryle), oxydes de phosphine ou H-phosphonates a été développée. Cette méthode permet d accéder à des butadiénylphosphines présentant des propriétés stériques et électroniques variées, ainsi que des oxydes de butadiénylphosphines et des butadiénylphosphonates avec de bons rendements. Ces deux dernières familles de composés ont été exploitées dans des réactions de réduction chimiosélective afin de proposer un accès aux butadiénylphosphines complémentaire à celui offert par le couplage direct entre la diphénylphosphine et les bromobutadiènes et une voie de synthèse inédite à des butadiénylphosphines primaires fonctionnalisées. Enfin, la première réaction d hydrophosphination efficace et régiosélective d alcènes catalysée au fer a été mise au point au cours de cette thèse, offrant pour la première fois un accès régiosélectif soit aux adduits anti-Markovnikov, soit aux adduits Markovnikov en modifiant uniquement le degré d oxydation des sels de fer utilisés (FeCl2 ou FeCl3).This thesis was devoted to the development of new and environmental friendly catalytic systems for the synthesis of C-P bonds. First, a general and effective synthetic method was developed based on the copper-catalyzed cross-coupling reaction of differently functionalized bromobutadienes and various secondary phosphines (diaryl, dialkyl- and alkylaryl), diphenylphosphine oxide or H-phosphonates. This method provides a straightforward access to butadienylphosphines with different steric and electronic properties as well as butadienylphosphine oxides and butadienylphosphonates in good yields. These two last families were engaged in chemoselective reduction reaction to obtain a complementary access to butadienylphosphines and an unprecedented route to functionalized primary butadienylphosphines. Finally, the first regioselective and efficient iron-catalyzed hydrophosphination reaction of alkenes was developed, offering for the first time a regioselective entry either to anti-Markovnikov or Markovnikov adducts according to the oxidation state of the iron salts, FeCl2 or FeCl3.CAEN-BU Sciences et STAPS (141182103) / SudocSudocFranceF

Pallado-Catalyzed Cascade Synthesis of 2-Alkoxyquinolines from 1,3-Butadiynamides

A novel synthesis strategy to access 2-alkoxyquinoline derivatives via a palladium-driven cascade reaction is disclosed. Unlike classic methods based on the alkylation of 2-quinolones with alkyl halides, the present method benefits from the de novo assembly of the quinoline core starting from 1,3-butadiynamides. Palladium-catalyzed reaction cascades with N-(2-iodophenyl)-N-tosyl-1,3-butadiynamides and primary alcohols as external nucleophiles proceed under mild reaction conditions and selectively deliver a variety of differently functionalized 4-alkenyl 2-alkoxyquinolines in a single batch transformation

From ynamides to organic electronics: a new synthesis of 2-tosylamido and 2,5-bis-(tosylamido)-thiophenes

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From ynamides to organic electronics: a new synthesis of 2-tosylamido and 2,5-bis-(tosylamido)-thiophenes

International audienc