Triphenylphosphine → HCID 19883719, compound

Participants

Reaction Steps

9.3 g of 1,6-dibromohexane and 5 g of triphenylphosphine were stirred under argon at 100° for 1 hour. The reaction mixture was subsequently cooled and chromatographed on 90 g of silica gel with methylene chloride/methanol 95:5. The 6-bromohexyl-phosphonium bromide (6.37 g, 65%) obtained was treated with 35 ml of a 33 percent solution of dimethylamine in ethanol and stirred at room temperature for 24 hours under argon. The solution was evaporated and the residue was dried carefully in a high vacuum. The 6-(dimethylamino)hexyl-triphenylphosphonium bromide hydrobromide obtained was suspended in 50 ml of tetrahydrofuran, whereupon the suspension was treated portionwise at 0° with 2.09 g of potassium t-butylate. The mixture was stirred at 0° for 15 minutes. Subsequently, a solution of 1.86 g of 4-benzoyl-benzaldehyde [Tetrahed. Lett. 24, 4287 (1983)] in 10 ml of tetrahydrofuran was added thereto at 0° and the mixture was stirred at room temperature for 18 hours. The reaction mixture was evaporated. The residue was taken up in 100 ml of 1N hydrochloric acid and extracted three times with 100 ml of ether. The aqueous phase was made basic with 2N sodium hydroxide solution while cooling with ice and extracted three times with methylene chloride. The organic phases were dried over magnesium sulphate and evaporated. The crude product obtained was chromatographed on 100 g of neutral aluminium oxide (activity grade III) with methylene chloride/ethyl acetate 95:5. After evaporation there were obtained 1.98 g (31%) of 4-[(Z)-7-(dimethylamino)-1-heptenyl]benzophenone as a colourless oil.

Provenance & Evidence