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Accueil > Les équipes > Réactivité organométallique et catalyse pour la synthèse (ROCS) > Thèmes de recherche

New Catalytic Transformations

par ricci - publié le

Catalytic Domino Transformations

Domino Transformations allow the generation of several new bonds in a single synthetic operation, starting from simple substrates. The projects of the team deal with the study of original catalytic enchainements generally involving one or more transition metals.

Pd-Catalyzed Domino Carbonylative-Decarboxylative Allylation : an Easy and Selective Monoallylation of Ketones. In the presence of an allyl alcohol, α-chloroacetophenones undergo an allyloxycarbonylation reaction followed by in situ decarboxylative allylation to selectively afford the corresponding monoallylated ketones via a Pd-catalyzed domino sequence. The scope of the reaction was extended to substituted α-chloroacetophenones as well as various allyl alcohols.

Chem. Commun. 2012, 48, 5889-5891

Pd-Catalyzed Asymmetric Synthesis of N-Allenyl Amides and Their Au-Catalyzed Cycloisomerizative Hydroalkylation : A New Route Toward Enantioenriched Pyrrolidones. Gold-catalyzed cycloisomerizative hydroalkylation of N-allenyl amides affords regioselectively 4-vinyl-γ-lactams. This transformation is stereospecific and takes place with a total axis-to-center chirality transfer. The required enantioenriched N-allenylamide is successfully obtained from an original Pd-catalyzed dynamic kinetic asymmetric transformation.

Chem. Eur. 2012, 18, 3840-3844

Dual Reactivity of O-α-Allenyl Esters Under Palladium(0) Catalysis : From Carbopalladation / Allylic Alkylation Domino Sequences to Decarboxylative Allenylation. In a mechanistically-oriented study, O α-allenyl esters have been evaluated aspotential substrates for Pd-catalyzed carbopalladation / allylic alkylation domino sequences and decarboxylative allenylation reactions. The domino sequence turned out to be feasible only with electron-deficient aryl iodides, thereby showing a narrower potential than that previously observed with the malonamide-based series. The decarboxylative allenylation of O α-allenyl esters was also tested and turned out to be practicable with β-keto-ester-based substrates and using specific basic conditions. Plausible reaction mechanisms are porposed to account for the observed reactivities.

J. Organomet. Chem. 2012, 714, 53-59

Allylic Alkylation and Ring-Closing Metathesis in Sequence : a Successful Cohabitation of Pd and Ru. An allylic alkylation / ring-closing metathesis domino catalytic process, wherein a palladium and a ruthenium catalyst are concomitantly present in the reaction mixture from the outset of the reaction, has been developed. Evidence for Grubbs’ catalysts activity in allylic alkylation has been found.

Org. Lett. 2008, 10, 405-408

Phosphine-Free Palladium-Catalyzed Allene Carbopalladation/Allylic Alkylation Domino Sequence : a New Route to 4-(α-Styryl) γ-Lactams. Without Phosphines ! 4-(α-Styryl) γ-lactams were synthesized via a phosphine-free palladium-catalyzed carbopalladation/allylic alkylation domino sequence. The cyclization was totally regio- and diastereoselective in favour of the 3,4-trans-disubstituted γ-lactam. The process was successfully applied to the synthesis of a new aza-analog of (+)-oxo-parabenzlactone.

Chemistry a European Journal, 2009, 15, 4224-4227

Pseudo-Domino Palladium-Catalyzed Allylic Alkylation/Mizoroki-Heck Coupling Reaction : a Key Sequence toward (±)-Podophyllotoxin. A formal synthesis of podophyllotoxin was carried out in nine steps. The key pseudo-domino step was accomplished through the succession of an intermolecular palladium-catalyzed allylic alkylation and an intramolecular Mizoroki-Heck coupling reaction.

Tetrahedron Lett. 2008, 49, 760–763

Enantioselective Catalysis

Enantioselective γ-Lactam Synthesis via Palladium-Catalyzed Intramolecular Asymmetric Allylic Alkylation. A Pd(0)-catalysed intramolecular allylic alkylation in the presence of (R)-3,5-tBu-MeOBIPHEP takes place in up to 92:8 er in agreement with DFT calculations and provides easy access to enantio-enriched disubstituted γ-lactams.

Synlett, 2009, 1441-1444

Enantioselective Synthesis of Aryl Sulfoxides via Palladium-Catalyzed Arylation of Sulfenate Anions. Arylation of various sulfenate anions generated from β-sulfinyl esters by retro-Michael reaction in the presence of palladium(0) and enantiopure ligands gave the corresponding aryl sulfoxides in enantio-enriched form. The Josiphos-type ligand (R)-(S)-PPF-t-Bu2 turned out to be the best ligand tested, allowing ee’s up to 83% in a predictable sense.

Org. Lett. 2007, 9, 5493-5496

C-H Bond Activation

Striking AcOH Acceleration in Direct Intramolecular Allylic Amination Reaction. AcOH as the solvent enables extraordinarily fast and efficient Pd(II)-catalysed direct intramolecular allylic aminations, assisting the benzoquinone-mediated palladium reoxidation and ionisation of the intermediate palladium complexes. The structural and energetic aspects of such a key step of the catalytic cycle are illustrated by means of a detailed DFT analysis.

Chemistry a European Journal, 2009, 15, 42, 11078-11082.