Bernard Cazes

Synthesis of Allylic Amines Through the Palladium- Catalyzed Hydroamination of Allenes.

The palladium-catalyzed addition of amines to allenes in the presence of triethylammonium iodide leads to allylic amines.

Pauson-Khand reaction with allenic compounds I: Synthesis of 4-alkylidene-2-cyclopentenones

Abstract The intermolecular cobalt-mediated cocyclisation of alkynes and allenes is efficiently promoted by N-methylmorpholine oxide at room temperature and leads to 4-alkylidene-2-cyclopentenones.

Pauson-Khand cycloaddition of α,ω-allenynes

Abstract The intramolecular cobalt-mediated reaction of α,ω-allenynes 8 leads to bicyclic dienones 10 and α-alkylidenecyclopentenones 11; regioselectivity depends on the substitution pattern of the allenic moiety.

Palladium-catalyzed addition of malonate type compounds to allenes via a hydropalladation process

Abstract The palladium and base-catalyzed addition of malonates and acetylacetates to allenic hydrocarbons affords allylated dicarbonyl compounds. Results account likely for an unprecedented hydropalladation process of the allenic unit which leads to a π-allylpalladium intermediate.

Pauson-Khand reaction with allenic compounds II: Reactivity of functionalized allenes

Abstract The cobalt-mediated cycloaddition of alkynes with functionalized allenes were shown to lead to different 4- and 5-alkylidenecyclopent-2-enones 4–6. Regioselectivity depends on both steric and electronic effects of the substituents.

Reactivity of 1-alkoxy π-allylpalladium complexes

Abstract The palladium-catalyzed allylic substitution of 3-alkoxy-2-propenyl acetates and carbonates with various carbonucleophiles occurs alpha to the alkoxy group.

Carbopalladation-sulphonylation of allene: A versatile preparation of 2-vinyl or 2-aryl allyl sulphones

Abstract The allene carbopalladation process can be realized with various vinylic or aromatic derivatives, in the presence of sodium benzenesulphinate, and allows the preparation of the entitled sulphones.

Palladium-catalyzed substitution of acrolein acetals by β-dicarbonyl nucleophiles

β-Dicarbonyl compounds with a high acidity (pKa < 8–9) easily react with acrolein diethyl or dimethyl acetals in the presence of a palladium catalyst and lead to allyl ethers. Some of these can be thermodynamically isomerized to enol ethers during their purification or substituted by another soft carbonucleophile under similar conditions, because of the leaving group property of the enolate of these stabilized β-dicarbonyl unit.

Synthesis of α or β-aminodienes via the carbopalladation of 1,2-propadiene

Abstract The allene carbopalladation process can be realized in the presence of the triflates derived from 3-piperidone and 4-piperidone leading to cyclic α or β-aminodienes.

Stereoselectivity of the carbopalladation-functionalization of allenic compounds: A mechanistic study

Abstract A comparison between the stereo-outcome of the carbopalladation-functionalization of monosubstituted allenes and the palladium-catalyzed substitution of dienic acetates 1 and 4 by a malonate anion shows that the same π-allyl intermediate should be involved in both processes. During this study, an influence of the counterion of the palladium complex on the stereoselectivity of the process was clearly demonstrated.