A detailed analysis of the distances showed 30 % of the poses with either the primary or the secondary alcohol group close to the acylenzyme carbonyl function. Among these poses, both hydroxy groups came at a distance below 4 Å that is necessary for the nucleophilic attack and the subsequent establishment of the ester bond. A similar result was obtained with the vinyl propionate chain. In the case of short acyl chains, these results suggested that the selectivity observed is due to the intrinsic reactivity of both hydroxy groups, rather than steric hindrance or the bad orientation of the substrates. On the other hand, when dealing with longer alkyl chains, such as those present in vinyl hexanoate and octanoate, steric hindrance became more significant. This led to less buried poses and increased distances between DHLc and the catalytic residues. Only 3 % and 1 % of the poses came close to the catalytic residues in the presence of the hexanoyl chain and the octanoyl chain, respectively. Moreover, only the primary alcohol of DHLc could reach the acyl-enzyme carbonyl function. These results suggest that as the acyl donor chain length increases, the binding modes of the enzyme-substrate complex become less favorable and the steric effect plays a more significant role in determining selectivity. This also correlates with a reduced reactivity compared to vinyl esters with a shorter side chain, resulting in a lower conversion.