7-Methoxy-1,2,3,4-tetrahydronaphthalen-1-one → 1-Methylene-7-methoxy-1,2,3,4-tetrahydronaphthalene

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Reaction Steps

n-Butyl lithium (1.6M, 6.2 mL, 9.92 mmol) was added dropwise to a THF (20 mL) solution containing methyltriphenylphosphonium bromide (3.65 g, 10.22 mmol) cooled in an ice bath. The solution was stirred at room temperature for 3 hours. A THF (5 mL) solution of 7-methoxy-3,4-dihydronaphthalen-1(2H)-one (1 g, 5.68 mmol) was added dropwise. The solution was then stirred at 60° C. overnight. The solution was partitioned between ethyl ether and water. The organic phase was washed with water (3×) and brine and dried over MgSO4. The filtered solution was concentrated and the residue purified by silica gel chromatography using a hexanes/ethyl acetate gradient to give the title compound. 1H NMR (500 MHz, CDCl3): δ 7.25 (d, J=2.6 Hz, 1H); 7.10 (d, J=8.3 Hz, 1H); 6.86 (dd, J=2.6, 8.4 Hz, 1H); 5.55 (s, 1H); 5.05 (s, 1H); 3.88 (s, 3H); 2.86 (t, J=6.3 Hz, 2H); 2.61 (t, J=6.2 Hz, 2H); 1.96-1.92 (m, 2H). LCMS1 3.79 min. (M+1)=175

Provenance & Evidence