Trifluoroacetic acid → 1-Cyano-5,6-dimethoxy-3-phenyl-3,4-dihydronaphthalene

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Reaction Conditions

Reaction Steps

To a suspension of 10 g (35 mmol) of 5,6-dimethoxy-3-phenyl-1,2,3,4-tetrahydronaphthalen-1-one, the product of Example 1, was added 7.5 g (75.6 mmol) of trimethylsilyl cyanide (commercially available from Aldrich Chemical Company) and approximately 50 mg of anhydrous aluminum chloride (AlCl3). The reaction mixture was heated at 60° C. for 3 h then cooled to ambient temperature and diluted with 150 mL of toluene. The volume of the reaction mixture was reduced in vacuo to approximately 50 mL. The resultant trimethylsilyl adduct was dehydrated by treatment with 15 mL of trifluoroacetic acid and 100 mg of p-toluenesulfonic acid in 200 mL of toluene at reflux temperature for 1 h. The reaction mixture was cooled to ambient temperature, the layers separated and the organic layer washed with water, aqueous sodium bicarbonate solution and brine, dried over anhydrous magnesium sulfate, filtered and concentrated under reduced pressure to a colorless oil. The oil was purified by column chromatography on silica gel eluted with 20% ethyl acetate in hexane to give 8.5 g (83% yield) of the title compound, m.p. 109°-110° C.

Provenance & Evidence