In addition, it seems that a certain degree of flexibility of the acyl chain plays a crucial role in the obtention of favourable enzymesubstrates complexes. This partially elucidates why aromatic vinyl esters, possessing a rigid aromatic ring did not produce a reaction with DHLc. This was observed even for substrates 11 and 12, which bear an electron-deficient aromatic cycle which theoretically increases the electrophilic character of the carbonyl carbon. This assumption was confirmed through docking simulations between DHLc and methoxybenzoyl-and methoxyphenoyl-CAL-B targets, as no pose came within a 5 Å radius from the acyl-enzyme carbonyl function.