四氢吡喃醚-四聚乙二醇

反应条件: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

实验步骤: To a 20 mL solution of methylene chloride containing tetraethylene glycol (15 mmol, 2.91 g) and toluenesulfonic acid (20 mg) was added dropwise via syringe 3,4-dihydro-2H-pyran (12 mmol, 1.0 g, 1.1 mL). The reaction mixture was stirred for 3.5 h, and the solvent was removed by rotary evaporation. Mono-tetrahydropyran 1 was isolated by flash chromatography on silica eluting with 1:1 tetrahydrofuran/methylene chloride, affording 1.82 g of a clear, colorless oil (44% yield). 1H NMR (400 MHz, CDCl3): δ4.61 (dd, 1H, J1 =J2 =4 Hz), 4.6-4.8 (m, 2H), 3.69 (t, 2H, J=7 Hz). the solvent was removed by rotary evaporation