Trimethylsilylacetylene → 4,4-Dimethyl-7-((trimethylsilyl)ethynyl)-3,4-dihydronaphthalen-1(2H)-one

Participants

Reaction Steps

To a solution (flushed for 15 minutes with a stream of argon) of 7 g (27.6 mmol) of 3,4-dihydro-4,4-dimethyl-7-bromo-1(2H)-naphthalenone (Compound B) in 150 ml of triethylamine was added 0.97 g (1.3 mmol) of bis(triphenylphosphine)palladium(II) chloride and 0.26 g (1.3 mmol) of cuprous iodide. The solution mixture was flushed with argon for 5 minutes and then 39 ml (36.6 mmol) of (trimethylsilyl)acetylene was added. The reaction mixture was sealed in a pressure tube and placed in a preheated oil bath (100° C.) for 24 hours. The reaction mixture was then filtered through Celite, washed with Et2O and the filtrate concentrated in vacuo to give crude 7-(trimethylsilyl)ethynyl-3,4-dihydro-4,4-dimethylnaphthalen-1(2H)-one. To a solution of this crude TMS-acetylenic compound in 50 ml of methanol was added 0.6 g (4.3 mmol) of K2CO3. The mixture was stirred for 8 hours at ambient temperature and then filtered. The filtrate was concentrated in vacuo, diluted with Et2O, washed with water, 10% HCl and brine, dried over MgSO4 and concentrated in vacuo. Purification by column chromatography (silica, 10% EtOAc-hexane) yielded the title compound as a white solid. PMR (CDCl3): δ 1.39 (6H, s), 2.02 (2H, t, J=7.0 Hz), 2.73 (2H, t, J=7.0 Hz), 3.08 (1H, s), 7.39 (1H, d, J=8.2 Hz), 7.61 (1H, dd, J=1.8, 8.2 Hz), 8.14 (1H, d, J=9 1.8 Hz).

Provenance & Evidence