Organic electrochemistry and radical/radical ion chemistry / Électrochimie organique et chimie des radicaux/radicaux ions

本研究的主要目的是确定影响活性中间体(自由基、自由基离子和化学吸附氢(HADS))反应性的因素，并在分子水平上了解这些因素是如何影响它们的反应性的。I.酰胺基的反应性。-我们将合成限制在pi电子态(pi轨道上未配对的e-)反应的环酰胺的新模型前体，并允许比较pi和sigma(sigma键平面上的未配对e-)态的反应性。II.N-取代内酰胺的环收缩-我们发现N-氯内酰胺和N-氧甲酰内酰胺(6和7元环)的光解得到了相应的环收缩氮杂环，在迁移碳上保持了100%的构型。拟议的研究将涉及：机理研究(内酰胺环不同位置的取代基、环的构象偏差和同位素标记的影响)；开发N-羟基内酰胺的一般合成；N-氨基内酰胺的合成和重氮化；在合成N-杂环天然产物方面的应用。III.电有机化学-3a硝基阴离子的裂解-我们将通过电还原产生一系列1-硝基/环丁烷和1-(4-硝基苯基)-环丙烷/环丁烷的自由基阴离子，这些阴离子在1和2位(烷基、给电子/吸引基团)具有不同的取代基，并用循环伏安法(均相氧化还原催化非常快速的裂解)、库仑滴定法和制备电解(产物鉴定)来确定裂解的类型(均溶基和异溶基)及其裂解速率。3B.电催化加氢(ECH)-有机化合物的ECH涉及HADS(通过还原水在电极表面生成)与被吸附的组织的反应。底物。对单晶的表面和动力学研究的目的是：1)确定/了解影响效率和选择性的因素；2)确定氢化活性的H(ADS)的性质；3)确定电催化剂和反应条件如何影响速率(氢化与H脱附)。

The main objective of my research is to identify factors which influence the reactivity of reactive intermediates (radicals, radical ions, and chemisorbed hydrogen (Hads)), and to comprehend at the molecular level, how these factors affect their reactivity. I. REACTIVITY of amidyl radicals.- We will synthesize new model precursors of cyclic amidyls constrained to react in the pi electronic state (unpaired e- in a pi orbital) and precursors allowing to compare the reactivity of the pi and sigma (unpaired e- in the plane of the sigma bonds) states. II. RING CONTRACTION of N-substituted lactams.- We discovered that photolysis of N-chloro- and N-Omesyl-lactams (6- and 7-membered ring) gives the corresponding ring-contracted nitrogen heterocycle with 100% retention of configuration at the migrating carbon. The proposed research will involve: mechanistic studies (influence of substituents at various positions of the lactam ring, of the conformational bias of the ring, and of isotopic labelling); development of general syntheses of N-hydroxylactams; synthesis and diazotation of N-aminolactams; applications to the synthesis of N-heterocyclic natural products. III. ELECTROORGANIC CHEMISTRY.- 3a. Cleavage of nitro radical anions.- We will generate, by electroreduction, the radical anion of a series of 1-nitrocyclopropanes / cyclobutanes and 1-(4-nitrophenyl)-cyclopropanes / cyclobutanes having various substituents at positions 1 and 2 (alkyl groups, electron-donating /-attracting groups) and determine the type of cleavage (homolytic vs. heterolytic) and their rate of cleavage using cyclic voltammetry (homogeneous redox catalysis for very rapid cleavage), coulometry and preparative electrolysis (product identification). 3b. ElectroCatalytic Hydrogenation (ECH).- ECH of an organic compound involves reaction of Hads (generated on the electrode surface by reduction of water) with the adsorbed org. substrate. Surface and kinetic studies on single crystals aims at i) identifying / understanding the factors influencing the efficiency and selectivity, ii) identifying the nature of H(ads) active in hydrogenation, and iii) determining how the electrocatalyst and reaction conditions affect the rates (hydrogenation vs. H desorption).