Water → (R)-3-(4-iodobenzyloxy)propane-1,2-diol

(S)-(+)-2,2-Dimethyl-1,3-dioxolane-4-methanol (6, 1.17 g, 8.9 mmol) and 4-iodobenzylbromide (2.5 g, 8.4 mmol) were refluxed under Dean-Stark conditions in toluene (80 mL) in the presence of KOH (8.8 g, 154.0 mmol) for 12 h. The reaction mixture was allowed to cool down and H2O (30 mL) was added. After separation of the phases the water layer was washed with toluene (2×15 mL). Combined organic layers were washed with H2O (30 mL) and concentrated in vacuo. The residue was treated with 80% aq. AcOH (25 mL) for 48 h at rt. The solvent was removed in vacuo and the residue was co-evaporated twice with toluene/EtOH (30 mL, 5:1, v/v). The residue was dried under diminished pressure to afford (R)-3-(4-iodobenzyloxy)propane-1,2-diol (7, 100%, 2.3 g) as yellowish oil that was used in the next step without further purification.