Autor(es):
Dias, T. A.
; Durães, C.
; Esteves, Ana Paula
; Medeiros, Maria José
; Pletcher, D.
Data: 2013
Identificador Persistente: http://hdl.handle.net/1822/25659
Origem: RepositóriUM - Universidade do Minho
Descrição
Radical cyclisation continues to be a central methodology for the preparation of natural products containing heterocyclic rings.
Hence, some electrochemical results obtained by cyclic voltammetry and controlled-potential electrolysis in the study of electroreductive intramolecular cyclisation of ethyl (2S, 3R)-2-
bromo-3-propargyloxy-3-(2’,3’,4’,6’-tetra-O-acetyl-β-D-glucopyranosiloxy) propanoate (1) promoted by (1,4,8,11-tetramethyl-1,4,8,11-tetraazacyclotetra-decane)nickel(I), [Ni(tmc)]+,
electrogenerated at glassy carbon cathodes in ethanol and ethanol/water mixtures containing tetraalkylammonium salts, are
presented.
During controlled-potential electrolyses of solutions containing [Ni(tmc)]2+ and acetylated D-glucose-based bromo propargyl ester (1) catalytic reduction of the latter proceeds via one-electron cleavage of the carbon–bromine bond to form a radical
intermediate that undergoes cyclization to afford the substituted tetrahydrofurans.