Boron trifluoride etherate → 5,6-Dimethoxy-3,4-dihydronaphthalene-1-carbonitrile

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Reaction Steps

Tetralone 7 (1.7 g, 8.25 mmol) was added as a slurry in freshly distilled toluene (25 mL) to a dried flask with magnetic stirring. TMSCN (1.42 mL, 10.7 mmol) was added dropwise. After stirring for 10 min, BF3.OEt2 (1.57 mL, 12.38 mmol) was added with a syringe. The reaction was stirred at room temperature for 3 h, until no starting material remained. The reaction was quenched by pouring over 30 mL ice water and stirring vigorously. To this aqueous mixture were added 20 mL of Et2O, and the layers were separated. The aqueous layer was extracted twice more with Et2O and once with EtOAc. The combined organic layers were dried over Na2SO4, filtered, and evaporated under reduced pressure to afford a tan solid (1.7 g, 7.9 mmol, 96%) that was recrystallized from MeOH to yield fine, colorless needles; mp 138-140° C. (lit.36 mp 137-139° C.). 1H NMR: (300 MHz, CDCl3): δ 7.18 (d, 1H, J=8 Hz, ArH); 6.80 (d, 1H, J=8 Hz, ArH); 6.75 (t, 1H, J=4.6 Hz, ArCH2CH2CH); 3.88 (s, 3H, ArOCH3); 3.76 (s, 3H, ArOCH3); 2.87 (t, 2H, J=8 Hz, ArCH2); 2.44 (m, 2H, ArCH2CH2). EIMS (M+)=215.

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