title: N-Vinyl- and C-vinylpyrroles from azafulvenium methides. flash vacuum pyrolysis route to 5-Oxo-5H-pyrrolizines and 1-azabenzo[f]azulenes.
abstract: 1-Azafulvenium methides, generated from pyrrolo[1,2-c]thiazole-2,2-dioxides' thermal extrusion of sulfur dioxide, led to the synthesis of functionalized pyrroles. The intramolecular trapping of these transient 8pi 1,7-dipoles in pericyclic reactions, namely sigmatropic [1,8]H shifts and 1,7-electrocyclization, allowed the synthesis of N-vinylpyrroles and C-vinylpyrroles which, under flash vacuum pyrolysis conditions, are converted into 5-oxo-5H-pyrrolizines or 4-oxo-1,4-dihydro-1-aza-benzo[f]azulenes, respectively. These heterocycles can also be obtained directly from FVP of pyrrolo[1,2-c]thiazole 2,2-dioxides. The synthesis and X-ray structure of a new 6-oxocyclopenta[b]pyrrole derivative is also reported.
authors.affiliation: Departamento de Química, Universidade de Coimbra, 3004-535 Coimbra, Portugal. tmelo@ci.uc.pt
authors.forename: Teresa M V D
authors.initials: TM
authors.lastname: Pinho e Melo
authors.forename: Maria I L
authors.initials: MI
authors.lastname: Soares
authors.forename: António M d'A Rocha
authors.initials: AM
authors.lastname: Gonsalves
authors.forename: José A
authors.initials: JA
authors.lastname: Paixão
authors.forename: Ana Matos
authors.initials: AM
authors.lastname: Beja
authors.forename: Manuela Ramos
authors.initials: MR
authors.lastname: Silva