Water → HCID 66969318, compound

Participants

Reaction Steps

Ethyltriphenylphosphonium bromide (67.49 g, 181.79 mmol) is introduced in 675 ml of tetrahydrofuran. This white suspension is admixed over the course of 30 minutes with potassium hexamethyldisilazide (363.57 ml of a 0.5 M solution in toluene, 181.79 mmol), at a temperature between −5° C. and 0° C. The resulting red suspension is then stirred at room temperature for two and a half hours. Following dropwise addition (35 minutes) of 4′-isopropyl-2′-methoxyacetophenone (23.3 g, 121.19 mmol), in solution in 280 ml of tetrahydrofuran, the temperature rises to 29° C. The orange-brown reaction mixture is stirred at room temperature for four days. The batch is poured into 100 ml of water and admixed with ethyl acetate (250 ml). After 10-minute stirring, the organic phase is separated off and washed with water (40 ml) and brine (40 ml). After drying (Na2SO4) and removal of the solvent on a rotary evaporator, the residue is chromatographed on silica gel (eluent: ethyl acetate/hexane). This isolates more than 100% (26.44 g) of the product as an E/Z mixture, although one of the stereoisomers is predominant.

Provenance & Evidence