*2.2. DOLOs and TEMABF4 Synthesis*

DL-lactic acid (purity 90%), paraformaldehyde (reagent grade), paraldehyde (purity 98%), acetone (reagent grade), petroleum ether bp 40–60 ◦C, *p*-toluensulfonic acid monohydrated (*p*TsOH, purity 98%), Amberlite® IR-120 (H<sup>+</sup> form) and other solvents and chemicals used for the synthesis of DOLOs were purchased from Merck KGaA (Darmstadt, Germany).

Triethylmethylammonium chloride (purity ≤ 99%), ammonium tetrafluoroborate (purity ≤ 97%) and dry acetonitrile to prepare triethylmethylammonium tetrafluoroborate (TEMABF4) were purchased from Merck KGaA (Darmstadt, Germany).
