Sodium ethoxide → HCID 87903859, compound

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Reaction Conditions

Reaction Steps

13.7 g (50 mmol) of the product from step b) were dissolved in 125 ml of dichloromethane. 25.7 g (55 mmol) of 3-(5,5-dimethyl-1,3-dioxan-2-yl)but-2-enyltriphenylphosphonium chloride were added. At 0° C., 20.4 g of a 20% strength ethanolic solution of sodium ethoxide (60 mmol) were added over the course of 1 hour. The mixture was stirred at 0° C. for 1 hour and then 50 ml of semiconcentrated brine were added. The organic phase was separated off, washed once with 50 ml of semiconcentrated brine, dried over sodium sulfate and concentrated in a rotary evaporator at 20° C. down to 20 mbar. The residue (38.2 g) was purified by flash chromatography on silica gel (eluent: cyclohexane/methyl t-butyl ether 4:1). 19.9 g (93.4% of theory) of the title compound were obtained. For characterization, the product was dissolved by heating in 100 ml of ethyl acetate. 50 ml of diisopropyl ether were added to the hot solution and, after cooling to 0° C., the mixture was stirred for 1 hour. The crystals which formed were filtered off, washed with cold ethyl acetate/diisopropyl ether mixture (2:1 vol./vol.) and dried in a stream of nitrogen. Yield: 8.9 g of red crystals. Melting point 157.5 to 158° C. E11 (CHCl3): 2495 (423 nm), 2243 (448 nm).

Provenance & Evidence