title: Electrochemical syntheses of cyclo[n]pyrrole.
abstract: Cyclo[8]pyrrole was obtained efficiently when 3,3',4,4'-tetraethylbipyrrole was subjected to bulk electrolysis, with yields spanning a range from close to 0 % with tetra-n-butylammonium fluoride as the electrolyte, to almost 70 % when tetra-n-butylammonium hydrogensulfate was used for this purpose. These observations are consistent with the conclusion that the reaction is controlled by anion-related factors such as a specific templating effect. Note that cyclo[8]pyrrole was the only detectable macrocyclic product obtained from 3,3',4,4'-tetraethylbipyrrole under the conditions of the electrochemical oxidation. When similar electrolyses were performed by using 3,4-diethylpyrrole as the starting material, two products could be isolated, which were identified as being the cyclo[7]pyrrole and cyclo[8]pyrrole, respectively. Detailed analyses of the oxidized forms of cyclo[7]pyrrole and cyclo[8]pyrrole revealed that under the conditions of the electrolysis these latter species are not stable.
authors.affiliation: Département de Chimie Moléculaire, Laboratoire de Chimie Inorganique Rédox, UMR-5250, Université Joseph Fourier, BP 53, 38041, Grenoble Cédex 9, France.
authors.forename: Mihai
authors.initials: M
authors.lastname: Buda
authors.forename: Adriana
authors.initials: A
authors.lastname: Iordache
authors.forename: Christophe
authors.initials: C
authors.lastname: Bucher
authors.forename: Jean-Claude
authors.initials: JC
authors.lastname: Moutet
authors.forename: Guy
authors.initials: G
authors.lastname: Royal
authors.forename: Eric
authors.initials: E
authors.lastname: Saint-Aman
authors.forename: Jonathan L
authors.initials: JL
authors.lastname: Sessler