We investigated the effect of the acyl group size in the enantioselectivity of the acylation of propranolol, an amino alcohol used as β-adrenergic blocking agent. We applied a methodology frequently used to model enantioselectivity that is based on the hydrogen bonds present in the tetrahedral intermediate, which occurs in lipase-catalyzed reactions. We sampled the conformations of the tetrahedral intermediate corresponding to the esterification of both enantiomers of propranolol with ethanoyl and butanoyl, employing molecular dynamics simulation together with a quantum mechanics/molecular mechanics approach. We found that the population of these hydrogen bonds provides insight into the mechanism of the reaction. However, they are not conclusive about the role of the acyl group in the enantioselectivity. For both acyl groups, we found that the reaction from the Michaelis complex to the tetrahedral intermediate is more favorable for (R)-propranolol and the reaction from the tetrahedral intermediate to the enzyme/product complex is more favorable for (S)-propranolol.