N-Vinyl- and C-Vinylpyrroles from Azafulvenium Methides. Flash Vacuum Pyrolysis Route to 5-Oxo-5H-pyrrolizines and 1-Azabenzo[f]azulenes

• Autor(a) principal: Melo, Teresa M. V. D. Pinho e
• Data de Publicação: 2005
• Outros Autores: Soares, Maria I. L., Gonsalves, António M. d'A. Rocha, Paixão, José A., Beja, Ana Matos, Silva, Manuela Ramos
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10316/10278; https://doi.org/10.1021/jo050480i

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 8π 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.