title: Fe(II)/Et3N-Relay-catalyzed domino reaction of isoxazoles with imidazolium salts in the synthesis of methyl 4-imidazolylpyrrole-2-carboxylates, its ylide and betaine derivatives.
abstract: A simple approach was developed for the synthesis of methyl 4-imidazolylpyrrole-2-carboxylates from easily available compounds, 5-methoxyisoxazoles and phenacylimidazolium salts under hybrid Fe(II)/Et3N relay catalysis. The products were easily transformed into the corresponding 3-(5-methoxycarbonyl-1H-imidazol-3-ium-3-yl)pyrrol-1-ides, which in turn can be hydrolyzed under basic conditions into the corresponding betaines. A carbene tautomeric form of the 4-methoxycarbonyl-substituted imidazolylpyrrolides was trapped by reaction with sulfur affording the corresponding imidazolethiones under very mild conditions.
authors.affiliation: Institute of Chemistry, Saint Petersburg State University, Universitetskii pr. 26, 198504, St. Petersburg, Russia.
authors.forename: Ekaterina E
authors.initials: EE
authors.lastname: Galenko
authors.affiliation: Institute of Chemistry, Saint Petersburg State University, Universitetskii pr. 26, 198504, St. Petersburg, Russia.
authors.forename: Olesya A
authors.initials: OA
authors.lastname: Tomashenko
authors.affiliation: Institute of Chemistry, Saint Petersburg State University, Universitetskii pr. 26, 198504, St. Petersburg, Russia.
authors.forename: Alexander F
authors.initials: AF
authors.lastname: Khlebnikov
authors.affiliation: Institute of Chemistry, Saint Petersburg State University, Universitetskii pr. 26, 198504, St. Petersburg, Russia.
authors.forename: Mikhail S
authors.initials: MS
authors.lastname: Novikov
authors.affiliation: Institute of Earth Sciences, Saint Petersburg State University, University Emb. 7/9, 199034, St. Petersburg, Russia.
authors.forename: Taras L
authors.initials: TL
authors.lastname: Panikorovskii
keywords: NHC carbene; imidazole; isoxazole; pyrrole-2-carboxylate; relay catalysis