3-(Prop-2-ynyloxy)-2,2-bis((prop-2-ynyloxy)methyl)propan-1-ol (35). An aqueous solution of NaOH (40 wt %, 10 mL) was added to a solution of pentaerythritol (2.00 g, 14.7 mmol) in 15 mL of dimethylsulfoxide (DMSO). The solution was stirred at rt for 30 min. Propargyl bromide (97%, 9.8 mL, 110 mmol) was then added, and the solution was kept at rt for an additional 10 h. The reaction mixture was then poured into 150 mL of EtOAc and washed with H2O (50 mL × 2) as well as brine (50 mL). The organic layer was dried by Na2SO4 and filtered. The filtrate was concentrated, and the residue was purified by FC (EtOAc/hexane = 1/4). 2.29 g of yellowish oil 35 (yield: 62%). 1H NMR (200 MHz, CDCl3) δ: 4.13 (d, 6H, J = 2.4 Hz), 3.69 (d, 2H, J = 6.4 Hz), 3.56 (s, 6H), 2.43 (t, 3H, J = 2.4 Hz).
