3,4-dihydro-2H-pyran → Tetrahydropyranyl ether

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Reaction Steps

In 20 ml of methylene chloride were dissolved 2.13 g of 2-[(E)-3-(4-bromophenyl)-2-methylallyloxy]ethanol and 1.43 ml of 3,4-dihydro-2H-pyran and 20 mg of p-toluenesulfonic acid monohydrate was added to the resulting solution with ice-cooling, after which the resulting mixture was subjected to reaction at room temperature for 3 hours. Subsequently, 30 ml of methylene chloride and 20 ml of a saturated aqueous sodium hydrogen-carbonate solution were added to the reaction mixture, and the organic layer was separated, washed successively with 20 ml of water and 20 ml of a saturated aqueous sodium chloride solution, and then dried over anhydrous magnesium sulfate, after which the solvent was removed by distillation under reduced pressure. The residue thus obtained was purified by a column chromatography [Wako Silica Gel C-200, eluant: toluene:ethyl acetate (20:1 by volume)] to obtain 2.6 g (yield 93%) of oily tetrahydropyranyl ether of 2-[(E)-3-(4-bromophenyl)-2-methylallyloxy]ethanol.

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