Toluene → 8-(3-Fluorophenyl)-1,4-dioxaspiro[4.5]dec-7-ene

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Reaction Conditions

Reaction Steps

The compound (16) (74.6 g), p-toluenesulfonic acid (2.24 g) and toluene (350 ml) were mixed, and the mixture was heated under reflux for 3 hours while water being distilled was removed. The reaction mixture was cooled to 30° C., and then water (500 ml) and toluene (150 ml) were added and mixed to it. The mixture was then allowed to stand until it had separated into two phases, the organic and aqueous phases, and an extractive operation to an organic phase was carried out. The organic phase was fractionated, and washed sequentially with a saturated aqueous solution of sodium hydrogencarbonate and water, and then dried over anhydrous magnesium sulfate. Then, the solvent of the solution was distilled off under reduced pressure, and the residue was purified with a fractional operation by means of column chromatography using a mixed solvent of toluene and ethyl acetate (toluene:ethyl acetate=7:3 by volume) as an eluent and silica gel as a stationary phase powder and dried, giving 69.7 g of 8-(3-fluorophenyl)-1,4-dioxaspiro[4.5]dec-7-ene (17). The yield based on the compound (14) was 86.8%.

Provenance & Evidence