title: Rhodium(II)-Catalyzed Annulation of Azavinyl Carbenes Through Ring-Expansion of 1,3,5-Trioxane: Rapid Access to Nine-Membered 1,3,5,7-Trioxazonines.
abstract: The rhodium(II)-catalyzed denitrogenative coupling of N-alkylsulfonyl 1,2,3-triazoles with 1,3,5-trioxane led to nine-membered-ringed trioxazonines in moderate-to-good yields. 1,3,5-Trioxane, acting as an oxygen nucleophile, reacted with the α-aza-vinylcarbene intermediate, giving rise to ylide formation, which was probably the key step in the reaction. Triazoles that contained aryl substituents with various electronic and steric features on the C4 carbon atom were well-tolerated. The synthesis of trioxazonine derivatives was achieved through a one-pot, two-step procedure from 1-mesylazide and a terminal alkyne by combining Cu(I)-catalyzed 1,3-dipolar cycloaddition and rhodium-catalyzed transformations.
authors.affiliation: Leibniz-Institut für Katalyse an der Universität Rostock e.V., Albert-Einstein-Straße 29, 18059, Rostock, Germany.
authors.forename: Jola
authors.initials: J
authors.lastname: Pospech
authors.affiliation: Leibniz-Institut für Katalyse an der Universität Rostock e.V., Albert-Einstein-Straße 29, 18059, Rostock, Germany.|CNR-Istituto di Scienze e Tecnologie Molecolari (ISTM), Via C. Golgi 19, 20133, Milano, Italy.
authors.forename: Raffaella
authors.initials: R
authors.lastname: Ferraccioli
authors.forename: Nicole
authors.initials: N
authors.lastname: LaBerge
authors.affiliation: Leibniz-Institut für Katalyse an der Universität Rostock e.V., Albert-Einstein-Straße 29, 18059, Rostock, Germany.
authors.forename: Helfried
authors.initials: H
authors.lastname: Neumann
authors.affiliation: Leibniz-Institut für Katalyse an der Universität Rostock e.V., Albert-Einstein-Straße 29, 18059, Rostock, Germany. Matthias.beller@catalysis.de.
authors.forename: Matthias
authors.initials: M
authors.lastname: Beller
keywords: annulation; carbenes; heterocycles; rhodium; ring expansion