Using ab initio calculations coupled with a continuum solvation model (PCM), it was shown that an organic molecule, 1,4-benzenedimethanol, is able to make two hydrogen bonds with anion-molecule S(N)2 transition states. We have investigated the catalytic properties of this species for the SN2 reaction between acetate ion and ethyl chloride in DMSO solution. Our calculations predicts an activation free energy barrier of 26.1 kcal mol(-1) for the uncatalyzed mechanism and 20.2 kcal mol(-1) for the catalyzed mechanism, a drop in the activation barrier in relation to free reactants by 5.9 kcal mol(-1). This organocatalyst is also able to catalyze E2 reactions and for the present system, the free energy barrier for the E2 mechanism drops by 5.3 kcal mol(-1) due the action of the catalyst. Based on our theoretical data and even considering the formation of a complex between the acetate ion and the catalyst, we have estimated that the 1,4-benzenedimethanol mixed with the DMSO solvent should result in a powerful new solvent system, able to accelerate S(N)2 reactions by a factor as large as 10(3) in relation to pure DMSO. (c) 2005 Elsevier B.V. All rights reserved.