- Reaction entre solvant et especes intermediaires apparues lors de l'electroreduction-acylation de la fluorenone et de la fluorenone-anil dans l'acetonitrile
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The electrogenerated anions CH2CN- induce the conversion of the various reduction-acylation products of fluorenone 1a and its anil 1b in acetonitrile into 1a and 1b; this phenomenon is controlled by the fortuitous introduction of molecular oxygen.The CH2CN- anions catalyse the transformation of 1a and 1b into fluorenylideneacetonitrile (FlC=CHCN) 17, convertible into the nitriles FlC=CH(CN)=C(NH2)CH3 8, FlC=C(CN)CHFl 10, and FlC(CN)CH2CN 11.These observations allow us to interpret the formation of the products appearing during the electrolysis of fluorenone in acetonitrile in the presence of an equivalent of chloride or anhydride of ω-chloro acid.The products of reduction-acylation appear successively, followed by the nitriles, FlC(OH)CH2CH2CN 3a, 10, FlC(OH)CH2CN 24, and polymers.Because of its basicity the fluorenone radical anion promotes reactions with the solvent, olefin 17 being a preferred intermediate.Bis-fluorenol, fluorenol, and finally fluorene and found with 1a and the above products.
- Degrand, Chantal,Belot, Gerard,Compagnon, Paul-Louis,Gasquez, Francoise
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p. 2581 - 2589
(2007/10/02)
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- Electroreductive Cyclopropylcarbonylation of Aromatic Ketones and Their Schiff Bases
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Mono- and dicyclopropylcarbonyl derivatives have been obtained by electroreduction of fluorenone, benzophenone, fluorenone anil, and benzophenone anil in the presence of 1 equiv of 4-bromo(or chloro)butyryl chloride (1a or 1b).The electrolyses are carried out in DMF or MeCN according to two methods.In method A, 1a (or 1b) is added dropwise during the electrolysis.In method B, the total amount of 1a (or 1b) is added at the beginning of the experiment.The electrogenerated bases which are necessary to perform the cyclopropylcarbonylation reactions are either theradical anions of the depolarizers or their acylated anions.The distribution of the compounds and their yields, which are moderate, depend on two main factors which are the method applied and the solvent.It is shown that the properties of acid chlorides 1a and 1b differ in DMF and MeCN.The highest yields of cyclopropyl derivatives are reached in MeCN when method B is applied.However, in this solvent the acylation reaction is less specifically orientated than in DMF, and unexpected propionitrile derivatives are isolated.In the case of the anils, results of chemical reduction by alkali metals and electrochemical reduction are compared.
- Belot, Gerard,Degrand, Chantal,Compagnon, Paul-Louis
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p. 325 - 331
(2007/10/02)
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