Electroreductive intramolecular cyclization of bromoalkoxylated derivatives cat...

• Author(s): Medeiros, M. J. ; Neves, C. S. S. ; Pereira, A. R. ; Duñach, E.
• Date: 2011
• Persistent ID: http://hdl.handle.net/1822/13442
• Origin: RepositóriUM - Universidade do Minho
• Subject(s): Microemulsions; Electrosynthesis; Catalytic reduction; Intramolecular cyclisation; Nickel(II) complex
• Document Type: Article
• Language: English

Description

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 radicaltype 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.