Highly efficient synthesis of trans-β,γ-unsaturated-α-keto amides

International audienceA highly efficient, metal-free, and selective access to trans-β,γ-unsaturated-α-keto amides is described via peptidic coupling, involving easy to prepare trans-β,γ-unsaturated-α-keto acids and commercially available amines

1,3-Dicarbonyl compounds in stereoselective domino and multicomponent reactions

International audienceModern organic synthesis focuses on the discovery and the development of stereoselective multiple bond-forming transformations allowing the creation of several covalent bonds in a single operation. Hence, the number of steps required to obtain a target molecule is reduced, which nicely answers to the efficiency and economy criteria of "green chemistry". In this context, 1,3-dicarbonyl compounds are exceptional synthetic platforms due to the presence of four contiguous reaction sites. This functional group density allows cascades of elemental steps from simple substrates leading to the selective formation of elaborated molecular architectures. displaying a large functional diversity

Asymmetric organocascades involving the formation of two C-heteroatom bonds from two distinct heteroatoms

International audienceIn the vast and expanding world of enantioselective organocascades, the ones in which two C-heteroatom bonds are created from two distinct heteroatoms are rare. These fascinating domino processes constitutes real synthetic challenges and allow very convenient syntheses of diverse optically active heterocycles and also highly functionalised acyclic derivatives

Highly Efficient Access to Original Polycyclic Pyrrolopiperazine Scaffolds by a Three-Component Reaction with 1,3-Dicarbonyls.

International audienceMolecular sieves have been found to promote a new fast, environmentally friendly and experimentally simple mul- ticomponent domino reaction from 1,3-dicarbonyls for the synthe- sis of pyrrolopiperazine and azasteroid-like scaffolds, of potential synthetic and biological interests

Synthesis and palladium-catalysed isomerisation of fused polycyclic tetrahydrofurans : efficient and stereoselective one-pot domino construction of functionalised bridged bicyclo[n.2.1] ring systems

International audienceA new one-pot domino reaction for a general entry to functionalised bridged bicyclo[n.2.1] ring systems from α,α'-diactivated cyclic ketones and trans-1,4-dihalides is described. The sequence combines a base promoted C-O cycloalkylation reaction leading to fused polycyclic enol ethers and their in situ palladium-catalysed isomerisation

Michael Addition-Initiated Sequential Reactions from 1,3-Dicarbonyls for the Synthesis of Polycyclic Heterocycles

International audienceThis review aims to highlight the most significant recent developments on synthetic strategies involving consecutive, domino and multicomponent reactions featuring a Michael addition-initiating step for the synthesis of polycyclic heterocycles from 1,3-dicarbonyls. These original sequences constitute more efficient and eco-compatible alternatives to known synthetic approaches to heterocyclic compounds allowing for an even faster and highly desirable generation of molecular diversity and complexity

Exploiting the Reactivity of 1,2-Ketoamides: Enantioselective Syn-thesis of Functionalized Pyrrolidines and Pyrrolo-1,4-benzodiaze-pine-2,5-diones

International audienceA new strategy for the synthesis of optically active pyrrolo[ 1,4]benzo- diazepine-2,5-diones has been developed. The approach is based on an initial Michael addition of functionalized 1,2-ketoamides on nitroalkenes, with a reduction–double cyclization sequence leading to the desired substituted benzodiazepine

Activation of 1,2- and 1,3-Ketoamides with Thiourea Organocatalyst for the Enantioselective Domino Synthesis of Fuctionalized Cyclohexanes

International audienceSeveral reactive sites of 1,2- and 1,3-ketoamides were successively exploited in two complementary domino transformations for the synthesis of polysubstituted monocyclic or bridged bicyclic cyclohexanes, with the creation of up to six stereogenic centers. In both cases, a chiral bifunctional thiourea organocatalyst allowed efficient control of chirality in the final carbocycle

New Vanadium Keggin Heteropolyacids Encapsulated in a Silica Framework : Recyclable Catalysts for the Synthesis of Highly Substituted Hexahydropyrimidines Under Suitable Conditions

Solid acid catalysts based on the direct incorporation of the vanadium Keggin heteropolyacid (PMo11V) structure during the synthesis of silica by the sol–gel technique, in acidic media using tetraethyl orthosilicate (PMo11VSiO21, PMo11VSiO22, PMo11VSiO23, and PMo11VSiO24), were prepared and characterized by 31P-NMR, FT-IR, XRD, and textural properties (SBET). The acidic characteristics of the catalysts were determined by potentiometric titration with n-butylamine. A series of highly substituted hexahydropyrimidines were synthesized using these new materials, encapsulated in a silica framework, as catalyst in solvent-free conditions. This methodology requires short reaction time (1.5 h), a temperature of 80 °C in solvent free-conditions to obtain good to excellent yields of trifluoromethyl-hexahydropyrimidine derivatives. The Keggin catalyst embedded in the silica matrix is insoluble in polar media, which allows easy removal of the reaction products without affecting their catalytic activity.Centro de Investigación y Desarrollo en Ciencias Aplicada