p-Toluenesulfonic acid → 4-(Tetrahydro-pyran-2-yloxy)-but-2-yn-1-ol

Participants

Reaction Steps

3,4-Dihydro-2H-pyron (18.3 mL, 0.196 mol) in dichloromethane (30 mL) was added dropwise over 30 minutes to a stirred solution of 2-butyne-1,4-di-ol (16.832 g, 0.194 mol) and p-TsOH (2.236 g, 11.58 mmol) in DCM (250 mL) at 0° C. After addition, the mixture was stirred at room temperature for 4 hours. Sodium bicarbonate (858 mg) was added. The mixture was stirred for another hour. Water (10 mL) was added, followed by addition of saturated aqueous potassium carbonate (150 mL). The organic phase was separated and washed with brine (200 mL), dried over anhydrous sodium sulfate, and concentrated under reduced pressure (temperature below 25° C.). The residue was separated by flash column chromatography on silica gel using 5-25% EtOAc/hexane to afford 12.88 g of product (yield: 39%), along with 12.05 g of di-protected side product. 1H-NMR (CDCl3): δ 4.78 (t, J=3.0-3.3 Hz, 1 H), 4.37-4.21 (m, 4 H), 3.86-3.78 (m, 1 H), 3.55-3.50 (m, 1 H), 1.83-1.64 (m, 6 H).

Provenance & Evidence