abstract
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. (c) 2011 Elsevier Ltd. All rights reserved.
keywords
CARBON BOND FORMATION; RADICAL CYCLIZATION; ALKYL-HALIDES; MICROEMULSION STRUCTURE; ELECTROCHEMICAL REDUCTION; TETRAAZA MACROCYCLE; COMPLEXES; DIMETHYLFORMAMIDE; CATHODES; BROMIDES
subject category
Electrochemistry
authors
Medeiros, MJ; Neves, CSS; Pereira, AR; Dunach, E
our authors
Cristina Sofia dos Santos Neves
Junior Researcheracknowledgements
The authors would like to thank Prof. D. Pletcher for comments and helpful discussions. Part of this research was conducted while M.J.M. was a Visiting Scholar at University of Nice. In addition, we are grateful to the Fundacao Calouste Gulbenkian and FCT for partial financial support of this work.