An improved procedure has been developed using a catalytic amount of a nickel(11) complex in the efficient and selective electrochemical cyclization of propargyloxy and allyloxy bromo derivatives into substituted tetrahydrofurans using ethanol and ethanol-water mixtures as environmental-friendly systems. The reduction of the substrates proceeded via one-electron cleavage of the carbon-bromine bond to form a radical-type intermediate that undergoes cyclization to afford the tetrahydrofuran structures in good yields. (c) 2008 Elsevier Ltd. All rights reserved.