Reaction of pyrroles with ethyl 2-nitroso- and 2-azo-propenoates, and with ethyl cyanoformate N-oxide: a comparison of the reaction pathways
The reaction of ethyl 2-nitrosopropenoate 2a with 1 -methylpyrrole, 2.5-dimethylpyrrole and 2.5- diphenylpyrrole has been investigated. In every case the products result from highly regioselective attack at C-2 of the pyrrole by the electrophile. The azopropenoate esters 2b and 2c react similarly wi...
| Autor principal: | |
|---|---|
| Outros Autores: | |
| Formato: | article |
| Idioma: | eng |
| Publicado em: |
2012
|
| Assuntos: | |
| Texto completo: | http://hdl.handle.net/10400.1/936 |
| País: | Portugal |
| Oai: | oai:sapientia.ualg.pt:10400.1/936 |
| Resumo: | The reaction of ethyl 2-nitrosopropenoate 2a with 1 -methylpyrrole, 2.5-dimethylpyrrole and 2.5- diphenylpyrrole has been investigated. In every case the products result from highly regioselective attack at C-2 of the pyrrole by the electrophile. The azopropenoate esters 2b and 2c react similarly with pyrroles, to the extent that even 1 -(triisopropylsilyl)pyrrole is attacked exclusively at the 2-position by the azo ester 2b. In contrast, the nitrile oxide ethyl cyanoformate N-oxide 12 reacts at the 3-position of 2.5- dimethyl- and of 2,5-diphenyl-pyrrole. The reactions of the nitroso and azo esters with pyrroles are interpreted as Diels-Alder cycloadditions with inverse electron demand. |
|---|