3,4-dihydro-2H-pyran → 1-[2-Fluoro-4-(tetrahydro-pyran-2-yloxy)-phenyl]-ethanone

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A solution of 1-(2-fluoro-4-hydroxy-phenyl)-ethanone (130 mmol), 3,4-dihydro-2H-pyran (260 mmol) and a catalytic amount of pyridinium p-toluenesulfonate in CH2Cl2 (200 mL) was left overnight at room temperature. The organic phase was washed with 1 N NaOH (aq) (1×50 mL) and dried (K2CO3). Evaporation in vacuo gave a brown oil, that was purified by vacuum distillation. The desired product was isolated as clear oil in 74% yield: bp: 130-140 ° C./0.05 mbar. 1H-NMR (CDCl3) δ 7.86 (t, 1H), 6.87 (dd, 1H), 6.82 (dd, 1H), 5.49 (t, 1H), 3.86-3.78 (m, 1H), 3.67-3.61 (m, 1H), 2.59 (d, 3H), 1.97-1.60 (m, 6H).

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