3,4-dihydro-2H-pyran → 2-(4-bromo-3-fluorophenoxy)tetrahydro-2H-pyran

Beteiligte Stoffe

Reaktionsschritte

Pyridinium p-toluene sulfonic acid (789 mg, 3.1 mmol) was added to a solution of 4-bromo-3-fluorophenol (4.00 g, 20.9 mmol) and 3,4-dihydro-2H-pyran (3.52 g, 41.9 mmol) in dichloromethane (105 mL, 0.2M). After 2h the reaction was quenched with saturated aqueous sodium bicarbonate and the layers were separated. The aqueous layer was extracted with dichloromethane (2×). The organic layers were combined, dried (Na2SO4), filtered and concentrated to give a colorless oil. The material was loaded onto a 25g silica guard column and run on a 330g column with 0-5% EtOAc in heptane. Desired material was concentrated down yielding 1900 mg (33%) of a clear colorless oil.

Herkunft & Nachweise