Hydrostannation of Alkynes

International audienceIn this review, we present an overview of hydrostannation of alkynes until the end of 2018. Mechanism of the tin hydride addition on a triple bond is discussed at the beginning of this review in the presence of metal catalysts as Pd, Ru-based complexes, Lewis acids and under radical conditions. Then, stereoselectivity as well as regioselectivity aspects of tin hydride addition on the carbon triple bond is discussed using metal-catalysis, radical conditions or Lewis acids. In each of these items, the reactions will be studied for terminal alkynes and then, for internal alkynes. Applications of hydrostannation of alkynes using metal-catalysis is presented in a variety of total syntheses with Pd, Mo, Rh and Ru-complexes to provide highly functionalized vinyl stannanes derivatives as key-intermediates. Comparison with other methods providing vinyl stannanes using metallostannation followed by protonation is presented before the last section dealing with a summary of classical experimental conditions used to achieve the hydrostannation of alkynes

Recognition of Blurred Pieces of Discrete Planes

International audienceWe introduce a new discrete primitive, the blurred piece of a discrete plane, which relies on the arithmetic definition of discrete planes. It generalizes such planes, admitting that some points are missing and then permits to adapt to noisy discrete data. Two recognition algorithms of such primitives are proposed: the first one is a geometrical algorithm and minimizes the Euclidean distance and the second one relies on linear programming and minimizes the vertical distance

Concevoir un dispositif de formation ouvert et à distance sur le modèle des Moocs : pertinence et efficacité

Les Moocs, cours en ligne ouverts et massifs, remportent actuellement un grand succès médiatique. Ils ont inspiré la création d'un module de formation à petit effectif. Mais ce dispositif est-il pertinent ? Peut-on inférer son efficacité à partir d'une évaluation a priori ? Après avoir présenté différents Moocs et détaillé le dispositif de formation créé, nous présentons une analyse théorique qui s'appuie sur des études concernant l'efficacité des dispositifs de formation à distance. Les résultats sont à considérer avec prudence car l'impact de la taille du groupe ne sera évaluable que lors de la mise en ligne. Cette réserve posée, les hypothèses semblent être validées, ce que devra confirmer la mise en ligne du module. Entre effet de mode ou évolution profonde, l'impact des Moocs sur l'offre de formation en ligne est encore incertain

Synthesis of Substituted Benzils from Diarylalkyne Oxidation

International audienceIn this review, oxidation of diarylalkynes leading to functionalized benzils (di(het)aryl-1,2-diketones) is summarized. Some synthetic "one pot" transformations of internal arylalkynes leading to the construction of heterocycles are presented

Reconnaissance de morceaux de plans discrets bruités

mémoire de DEA, 37 pagesLa reconnaissance d'objets discrets est un sujet important en géométrie discrète et de nombreux travaux concernant les droites et les plans ont été réalisés. Nous nous intéressons à la notion d'objets discrets flous, correspondant à des objets discrets bruités, et à leur détection. Ces objets sont définis analytiquement et les algorithmes développés à partir de ceux-ci s'adaptent aux données bruitées par les méthodes d'acquisition, par exemple les données médicales issues de scanners, d'échographie, d'IRM... Dans ce mémoire nous nous intéresserons plus particulièrement aux plans discrets bruités. En introduisant la définition d'un morceau de plan discret flou, nous montrerons que le problème de le reconnaissance d'un tel objet est équivalent à celui du calcul de l'épaisseur d'un ensemble de points en dimension 3. Après une étude des méthodes existantes résolvant le calcul de l'épaisseur, un algorithme connu sera alors adapté pour résoudre le problème de la reconnaissance incrémentale des morceaux de plans discrets flous

Desulfurization of Thioketals into Methylene and Methyl Derivatives: Nickel or not Nickel?

International audienceIn this review, the desulfurization of thioacetals and thioketals leading to methyl and methylene derivatives is summarized through metal and metal-free methodologies. In the section concerning the use of metals for desulfurization reactions, we will be successively presenting and discussing all methods requiring Ni and Ni derivatives as reducing agents and other examples in which metals were used to generate solvating electrons as reducing species. The following section will concern the use of other desulfurizing agents as metal-hydrides (Bu3SnH, Et3SiH) and metal-free desulfurization reactions of thioketals. The functional group tolerance of the presented methods with functionalized and sensitive substrates will be discussed

Chlorotrimethylsilane and Sodium Iodide: A Remarkable Metal-Free Association for the Desulfurization of Benzylic Dithioketals under Mild Conditions

International audienceA novel metal-free process allowing the reductive desulfurization of various benzylic dithioketals to afford diarylmethane and benzylester derivatives with good to excellent yields is reported. At room temperature, this mild reduction process requires only the use of TMSCl and NaI in CH2Cl2 and tolerates a large variety of functional groups

Identification of gait stability indices for the rehabilitation follow-up of people with transtibial amputation: a preliminary study

Resuming activities of daily living after a lower limb amputation represents a challenge, especially because of the high risk of falling. Thus, rehabilitation initially focuses on stability. Despit..

Synthesis of 2-Substituted Trifluoromethylquinolines for the Evaluation of Leishmanicidal Activity.

International audienceThe synthesis of 2-substituted-trifluoromethylquinolines from aniline, trifluoromethylanilines, 3-aminoquinoline and trifluoromethylquinaldines is reported. In vitro antileishmanial evaluation of 2-alkyl, 2-alkenyl and 2-epoxypropyl-trifluoromethylquinolines is presented

One-pot hydrosilylation–protodesilylation of functionalized diarylalkynes: a highly selective access to Z-stilbenes. Application to the synthesis of combretastatin A-4

International audienceAn efficient stereoselective synthesis of Z-stilbenes has been developed from diarylalkynes via a new hydrosilylation-protodesilylation process. Scope and limitation of this method to prepare stereoselectively a wide range of (Z)-stilbenes in a one-pot way is presented. A concise application to the preparation of combretastatin A-4 (CA-4), a vascular targeting agent inhibitor of tubulin polymerisation is described