For MLA with its weak internal hydrogen bond between the hydroxy group and (preferentially) the carbonyl group, a solvent water has different options to coordinate. It can insert into the internal hydrogen bond, or add to either end, or even to the ester oxygen. Due to the activation barrier for the first process, jet experiments have to make sure that insertion is not kinetically hindered . This is important, because theory predicts insertion to be most stable. In this context, it is essential that there is experimental microwave evidence for the inserted structure , in which the solute also directs the dangling water hydrogen to one side.