Diastereoselective recognition of beta anomers of phenyl glucosides by a cyclobis(paraquat-p-phenylene) receptor: A computational study

The preference of a cyclobis(paraquat-p-phenylene) receptor for binding phenyl beta-glucopyranoside over the alpha- anomer was investigated by constant temperature molecular dynamics simulations conducted using the AMBER* force field and the GB/SA continuum solvation model. The energy difference between the complexes of the beta- and alpha- anomers in water was found to be 0.3 +/- 0.1 kcal . mol(-1) using a stochastic dynamics algorithm and 0.1 +/- 0.1 kcal . mol(-1) for a mired mode Monte Carlo/stochostic dynamics method. This same trend was found in gas phase simulations, in which the complex with the beta anomer was more stable by 0.4 +/- 0.1 kcal . mol(-1). In all cases the complex of the beta anomer was shown to be more stable, indicating a possible steric origin for the diastereoselectivity of binding.