Hydrochloric Acid → HCID 9834714, compound

Participants

Reaction Steps

887.3 mg (3.423 mmol) of palladium(II)-dichloride-diacetonitrile were dissolved in 325.0 ml of tetrahydrofuran. 2.243 g (8.530 mmol) of triphenylphosphine were added. The reaction mixture turned yellow and, after 6 minutes, turbid. The reaction mixture was stirred for 10 minutes at room temperature, whereafter 22.81 g (153.9 mmol) of (R)-methanesulfonic acid 1-methyl-prop-2-ynylester and 16.30 g (85.52 mmol) of 2-chloro-1-(2,5-difluoro-phenyl)-ethanone were added together with about 25 ml of totally 233.3 ml (256.6 mmol) of diethylzinc solution in toluene (1.1 M) dropwise. The temperature was permitted to rise to 36° C. The remaining diethylzinc solution was added dropwose within 12 minutes at 37–38° C., whereafter the temperature was prevented from rising over 39° C. After 40 minutes (temperature about 27° C.) the reaction mixture was poured onto 350 ml of ice-cold half-saturated aqueous sodium chloride solution, 500 ml of ethylacetate were added, the mixture was stirred for 5 minutes at room temperature, and 70 ml of 25% aqueous hydrochloric acid were added (everything in solution). The aqueous phase was washed once with 250 ml of ethyl acetate and the organic phases once with 150 ml of quarter-saturated aqueous sodium bicarbonate solution and once with 50 ml of 0.1N aqueous hydrochloric acid. The organic phases were combined, dried over sodium sulfate and evaporated to dryness. 24.85 g of (2R,3S)-1-chloro-2-(2,5-difluoro-phenyl)-3-methyl-pent-4-yne-2-ol were obtained, which were 70.5% pure and contained 86% of the stated diastereomer. Yield 83.1%.

Provenance & Evidence