2-[2-(oxan-2-yloxy)ethoxy]ethanol

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To 800 mL of CH2Cl2 were added diethylene glycol (57 mL, 0.6 mol) and p-toluenesulfonic acid monohydrate (5.7 g, 30 mmol) successively. Then tetrahydropyran (27.4 mL, 0.3 mol) was added dropwise at 0° C. The reaction mixture was stirred overnight and quenched with H2O, extracted with CH2Cl2, washed with H2O and brine successively, concentrated through rotary evaporation, and subjected to silica gel chromatography using CH2Cl2/MeOH as the eluent to afford compound 28 (32.5 g, 0.17 mol, 57% yield) as a clear oil: 1H NMR (500 MHz, CDCl3) δ 4.59 (t, J=4.0 Hz, 1H), 3.85-3.80 (m, 2H), 3.68-3.64 (m, 4H), 3.59-3.55 (m, 3H), 3.48-3.44 (m, 1H), 2.98 (br, 1H), 1.81-1.76 (m, 1H), 1.71-1.65 (m, 1H), 1.59-1.46 (m, 4H). quenched with H2O extracted with CH2Cl2 washed with H2O and brine successively concentrated through rotary evaporation

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To 800 mL of CH2Cl2 were added diethylene glycol (57 mL, 0.6 mol) and p-toluenesulfonic acid monohydrate (5.7 g, 30 mmol) successively. Then tetrahydropyran (27.4 mL, 0.3 mol) was added dropwise at 0° C. The reaction mixture was stirred overnight and quenched with H2O, extracted with CH2Cl2, washed with H2O and brine successively, concentrated through rotary evaporation, and subjected to silica gel chromatography using CH2Cl2/MeOH as the eluent to afford compound 28 (32.5 g, 0.17 mol, 57% yield) as a clear oil: 1H NMR (500 MHz, CDCl3) δ 4.59 (t, J=4.0 Hz, 1H), 3.85-3.80 (m, 2H), 3.68-3.64 (m, 4H), 3.59-3.55 (m, 3H), 3.48-3.44 (m, 1H), 2.98 (br, 1H), 1.81-1.76 (m, 1H), 1.71-1.65 (m, 1H), 1.59-1.46 (m, 4H). quenched with H2O extracted with CH2Cl2 washed with H2O and brine successively concentrated through rotary evaporation