Ugi post-condensation copper-triggered oxidative cascade towards pyrazoles

International audiencePyrazolidinones were prepared in a two-step sequence starting from a-hydrazonocarboxylic acids. After a four-component Ugi coupling, the resulting hydrazone was engaged in a copper triggered [3 + 2] cycloaddition/aerobic oxidation cascade. © 2011 Santos et al; licensee Beilstein-Institut

One-pot synthesis of oxazoles using isocyanide surrogates

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Des derives fluores aux acetyleniques: Etude de deux nouvelles reactions

SIGLEAvailable from INIST (FR), Document Supply Service, under shelf-number : T 84487 / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc

Des réactions multicomposants impliquant des isonitriles a la synthèse d'heterocycles

Ces travaux mettent en valeur les réactions multicomposants a base d'isonitriles dans différentes applications autour des réactions d'Ugi-Smiles et de Nef pour la synthèse de systèmes hétérocycliques complexes. Nous avons démontré la possibilité d'utiliser des 4-hydroxypyridine et pyrimidines dans des couplages Ugi-Smiles. Ces réactions ont été appliquées à la préparation d'analogues d'antipaludéens. Diverses applications radicalaires ont été explorées sur des adduits de Ugi et Ugi-Smiles ( chimie des xanthates, couplages oxydatifs d'indoles). Nous avons par ailleurs exploré la chimie des dihalogénoisonitriles dans différentes synthèses hétérocycliquesThis work highlights the potential of multicomponent couplings isocyanides in heterocyclic chemistry. Two axes were particularly investigated through the Ugi-Smiles coupling and the Nef reaction. We have demonstrated the reactivity of 4-hydrpxypyridines and pyrimidines in Ugi-Smiles coupling, these reactions have been applied to the synthesis of antimalarial analogues. Several applications of Ugi and Ugi-Smiles adducts have been explored using radical chemistry (xanthates as well as oxidative couplings). We have also explored the chemistry of dihalogenoisocyanides in various heterocyclic synthesisPALAISEAU-Polytechnique (914772301) / SudocSudocFranceF

Mannich reaction of trifluoroacetaldehyde hydrazones: a useful entry to trifluoromethyl substituted heterocycles

International audienceNH-aryl hydrazones derived from trifluoroacetaldehyde hemiacetal may be involved in efficient Mannich type reactions with formaldehydes and aromatic aldehydes. The resulting hydrazones are useful building blocks for the preparation of trifluoromethyl substituted heterocycles as shown by a straightforward preparation of 1,2-diazine derivatives under heating with β-ketoesters

Vers la synthèse totale de la paulitine

PALAISEAU-Polytechnique (914772301) / SudocSudocFranceF

Piperazine as Leaving Group in A3 Adducts: Fast Access to Alkynyl Indoles

International audienceThe A3 coupling between N-ethylpiperazine and electron-rich aromatic aldehydes forms adducts that may be easily used as electrophiles towards electron-rich heterocycles such as indoles. The removal of the piperazine moiety is triggered by the addition of 1,2-dibromoethane. Overall, the reaction provides efficient access to alkynyl indoles and pyrroles

Beyond the Ugi reaction: less conventional interactions between isocyanides and iminium species

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Passerini/Tsuji-Trost Strategy towards Pyrrole Derivatives

International audienceThe Passerini reaction of α,β‐unsaturated aldehydes affords suitable substrates for a Tsuji–Trost reaction with NH‐enamines. The latter behave as a 1,3‐bisnucleophile, which leads to the formation of pyrrole derivatives with five points of diversity through a Tsuji–Trost/Michael addition/aromatization cascade

Beyond the Ugi reaction: less conventional interactions between isocyanides and iminium species

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