Electroreductive intramolecular cyclization of bromoalkoxylated derivatives catalyzed by nickel(I) tetramethylcyclam in "green" media
The (1,4,8,11-tetramethyl-1,4,8,11-tetraazacyclotetra-decane)nickel(I), [Ni(tmc)]+, electrogenerated at glassy carbon cathodes is shown to be an effective catalyst for the intramolecular radical-type cyclisation of bromoalkoxylated derivatives 1 in alcohol and / or alcohol/water mixtures as well as...
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| Outros Autores: | , , |
| Formato: | article |
| Idioma: | eng |
| Publicado em: |
2011
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| Assuntos: | |
| Texto completo: | http://hdl.handle.net/1822/13442 |
| País: | Portugal |
| Oai: | oai:repositorium.sdum.uminho.pt:1822/13442 |
| Resumo: | The (1,4,8,11-tetramethyl-1,4,8,11-tetraazacyclotetra-decane)nickel(I), [Ni(tmc)]+, electrogenerated at glassy carbon cathodes is shown to be an effective catalyst for the intramolecular radical-type cyclisation of bromoalkoxylated derivatives 1 in alcohol and / or alcohol/water mixtures as well as in microemulsions made with cationic and anionic surfactants. The results obtained indicate that the reaction proceeds via cleavage of the carbon–bromine bond to form a radicaltype intermediate that undergoes cyclisation on the unsaturated C-C bond to afford substituted tetrahydrofurans. The reactions are more selective and take place at higher current density than when carried out in conventional aprotic solvents. |
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