Synthesis and structure of Ag(I), Pd(II), Rh(I), Ru(II) and Au(I) NHC-complexes with a pendant Lewis acidic boronic ester moiety

International audienceBifunctional Ag(I), Pd(II), Rh(I), Ru(II) and Au(I) complexes containing a NHC ligand and a pendant trivalent boron moiety have been synthesized in high yields. Fine-tuned reaction conditions were used to prevent potential ligand self-quenching or polymerization due to the eventual co-existence in situ of free NHC (Lewis base) and boronic ester (Lewis acid) in the same molecule

First studies directed towards the diastereoselective synthesis of the BCD tricyclic core of brownin F

International audienceThe BCD tricyclic core of brownin F was prepared in eight synthetic operations for the first time. Our synthesis features a diastereo-, chemo- and regioselective intramolecular [3 + 2] cycloaddition between a cyclic carbonyl ylide and a γ-alkylidenebutenolide

Straightforward one-pot stereoselective synthesis of substituted tetrahydrofurans from 1,3-butadienes and aldehydes.

International audienceA new and efficient multicomponent reaction involving a double-allylation sequence is reported. In situ generated bimetallic reagents are prepared from disilane and added onto a range of aliphatic aldehydes to afford a direct access to trisubstituted tetrahydrofurans in good to excellent diastereoselectivity (up to 70%)

Diels-Alder cycloaddition of o-quinonedimethides and alkylidene-5H-furan-2-ones: new and rapid access to lambertellol cores and arthrinone derivatives

International audienceAn efficient synthesis of deoxy-lambertellols was reported through a highly chemo- and diastereoselective intermolecular Diels-Alder cycloaddition between trans-1,2-disiloxybenzocyclobutenes and 2-methylproto- anemonine. Such transformation with d-substituted c- alkylidenebutenolides, to prepare new analogues of these tricyclic spirolactones, which would be very difficult to prepare by other ways, was also studied

Construction of spirolactones with concomitant formation of the fused quaternary centre - application to the synthesis of natural products

International audiencePolycyclic structures fused at a central carbon are of great interest due to their appealing conformational features and their structural implications in biological systems. Although progress in the development of synthetic methodologies towards such structures has been impressive, the stereoselective construction of such quaternary stereocentres remains a significant challenge in the total synthesis of natural products. This review highlights the progress in the formation of 1- oxaspiro[4.n]alkan-2-ones with concomitant formation of the quaternary spiro centre

Domino allylic amination/Sonogashira/heterocyclisation reactions: palladium-catalysed three-component synthesis of pyrroles

International audienceThree-component reactions with 3,4-diiodoalk-2-enoic derivatives, primary amines, and terminal alkynes proceeded to give trisubstituted pyrroles in fair to good yields in the presence of palladium and copper catalysts under mild reaction conditions

Trans-1,2-disiloxybenzocyclobutene, an adequate partner for the auto-oxisation: EPR/spin trapping and theoretical studies

International audienceThe auto-oxidation of trans-1,2-disiloxybenzocyclobutene was found to be very efficient, giving endoperoxide in quantitative yield. Each step of the mechanism of spin-forbidden addition of triplet oxygen O2 was studied by both EPR/spin trapping and theoretical studies

Grafting a homogeneous transition metal catalyst onto a silicon AFM probe: a promising strategy for chemically constructive nanolithography

International audienceWe report a novel approach to chemically selective lithography using an atomic force microscope (AFM) probe with immobilized homogeneous catalyst, potentially giving access to diverse nanoscale transformations of the surface-bound functional groups. This new concept was proven for the local epoxidation of an alkene-terminated self-assembled monolayer on silicon using H2O2 as an oxidant and a catalytic silicon AFM tip charged with manganese complexes with 1,3,7-triazacyclononane type ligands

Consecutive Reactions with Sulfoximines: Straightforward Synthesis of Substituted 5,5-Spiroketals

International audienceAn efficient sysnthesis of 5,5-spiroketals, i.e. 1,6-dioxaspiro[4.4]nonane derivatives, is described from 2-(sulfonimidoylmethylene)tetrahydrofurans involving a consecutive epoxide opening / oxa-Michael spiroketalization sequence. This methodology was applied to the very direct synthesis of chalcogran, a beetle pheromone

Expeditious synthesis and biological evaluation of new C-6 1,2,3-triazole adenosine derivatives A1 receptor antagonists or agonists.

International audienceThe synthesis of new C-6 1,2,3-triazole adenosine derivatives via microwave assisted 1,3-dipolar cycloaddition as key step is described. The binding on membranes of cells that over express A(1) adenosine receptors (A(1)AR) was also evaluated. Among them, four compounds increased cAMP production, in a dose-dependent manner acting as antagonists of the A(1)AR, while two compounds act as agonists