Geneviève Balme

FUNCTIONALIZED ACETYLENES AS VERSATILE BUILDING-BLOCKS FOR THE MULTICOMPONENT ASSEMBLING OF POLYSUBSTITUTED FURANS AND PYRROLES

- This review highlights the versatility of functionalized alkynes in the multicomponent construction of polysubstituted furan and pyrrole derivatives.

A Novel Palladium Catalyst for Cross‐Coupling of Allyl Acetates with Arylboronic Acids

The palladium-catalyzed coupling reactions of various arylboronic acids and allylic acetates take place readily under mild conditions. The choice of ligand in the palladium catalyst and the solvent are critical to the yields of coupled products.(© Wiley-VCH Verlag GmbH, 69451 Weinheim, Germany, 2002)

Carbopalladation des alkylidenecyclopropanes-I capture intermoleculaire de l'organopalladique intermediaire

Abstract The reaction of methylenecyclopropane and 1-cyclopropylidene pentane with iodobenzene or 2-bromopropene and a delocalized anion (issued from malonate or from a β-sulfonyl ester) in the presence of catalytic amounts of a palladium (O) complex leads to conjugated dienes or to styrenes 5 , 6 , 8 or 9 . These compounds are probably issued of the capture of a II-allylic complex which results from the rearrangement of the initially formed α-cyclopropanic σ-palladic complex. The same reaction with 7-methylene bicyclo [4,1,0] heptane 3 behaves differently since the formation of a II-allyl palladium complex is forbidden by stereochemical factors.

Palladium-mediated cascade or multicomponent reactions: A new route to carbo- and heterocyclic compounds

In recent years, new processes based on transition-metal-mediated intramolecular addition reaction of heteronucleophiles and stabilized carbon nucleophiles to unactivated alkenes and alkynes have been developed in our laboratory. In this article, we summarize a number of recent synthetic applications of these new processes. Emphasis is placed on the development of multicomponent reactions based on a Pd-mediated intramolecular cyclization coupled with a carbon-carbon bond-forming reaction. Applications of this methodology to the synthesis of natural lignans are also reported.

Solution-phase parallel tetrahydrofuran synthesis with propargyl alcohols and benzylidene-(or alkylidene-)malonates

A large array of 3-methylene tetrahydrofurans has been synthesized from propargylic alcohols and activated olefins. The reaction is promoted by copper iodide that is removed at the end of the reaction by simple filtration, affording the desired heterocycles in high yield and purity.

Integrated Transition Metal Catalysed Reactions: Synthesis of Polysubstituted 4‐(Phenoxymethyl)‐3‐pyrrolines and Their Isomers by One‐Pot Coupling of Propargylamines, Vinyl Sulfones (or Nitroalkenes) and Phenols

Polysubstituted 4-(phenoxymethyl)-3-pyrrolines and their isomeric 4-(phenoxymethylene)pyrrolidines have been prepared by sequential one-pot coupling of three components: a propargylamine, a vinyl sulfone (or nitroalkene) and a phenolic derivative. The methodology is based on the sequential integration of a Cu-catalysed cycloaddition and a Pd-catalysed allylic substitution reaction. (© Wiley-VCH Verlag GmbH, 69451 Weinheim, Germany, 2002)

Attaque nucleophile intramoleculaire d'organopalladiques issus de la carbopalladation d'alkylidenecyclopropanes.

Abstract The catalytic carbopalladation of alkylidenecyclopropanes 1 having in R1 an ω-nucleophilic group leads to cyclic compounds resulting from the attack of either the π-allyl palladium complex 4 or either the δ-palladium complex 5 . This last new process is only observed with delocalized carbon nucleophiles when a five-membered ring can be formed.

Three-component one-pot synthesis of functionalised (Z)-4-benzylidene (and alkenylidene) pyrrolidines

A three-component synthesis of stereodefined 4-benzylidene-(or alkenylidene)-pyrrolidines from simple, readily available starting materials is described. This one-pot process is initiated by a conjugate addition of a propargylamine to a gem-diactivated olefin subsequently followed by a carbopalladation involving an aryl halide (or vinyl triflate).

Synthesis of heterocycles via sequential Pd/Ru-catalysed allene insertion–nucleophile incorporation–olefin metathesis

Abstract A novel sequential palladium/ruthenium-catalysed three-component process is described involving allenylation of aryl/heteroaryl iodides to generate (π-allyl) palladium species which are intercepted by nitrogen nucleophiles to afford 1,6- and 1,7-dienes. Subsequent ring-closing metathesis affords N -heterocycles in good yield.

Amines as key building blocks in Pd-assisted multicomponent processes

Summary In the last few years, palladium-mediated three-component synthesis has emerged as an important synthetic methodology to gain access to nitrogen-containing structures. The latest developments in this area are discussed in this review.