Tetrahydrofuran → 7-Bromo-1-methyl-2-methylene-1,2,3,4-tetrahydronaphthalen-1-ol

Temperatur

-78 °C

Anhydrous THF (200 mL) was added to a flame dried flask charged with anhydrous cerium (III) chloride (3.90 g, 15.8 mmol) under dry nitrogen. The mixture was vigorously stirred for 2 hours to provide an opaque suspension. The suspension was cooled to −78° C. Methyllithium (1.6 M in diethylether) (9.89 mL, 15.8 mmol) was added to the suspension of cerium(III) chloride to produce a bright yellow solution of methylcerium(III) dichloride. After stirring for 1 hour at −78° C., a solution of 7-bromo-2-methylene-3,4-dihydronaphthalen-1(2H)-one from step C1 (1.5 g, 6.33 mmol) in THF (20 mL) was added. The reaction mixture was allowed to stir for 30 min at −78° C., then it was poured into an Erlenmeyer flask charged with saturated aqueous ammonium chloride solution. The aqueous mixture was extracted with ethyl acetate. The combined organic layers were washed with brine, dried over sodium sulfate, filtered, and concentrated in vacuo. The residue was purified using silica gel column chromatography (10:1 Hex/EtOAc) to afford 7-bromo-1-methyl-2-methylene-1,2,3,4-tetrahydronaphthalen-1-ol (0.670 g, 2.66 mmol, 42% yield) as a clear viscous oil. 1H NMR (500 MHz, chloroform-d) δ 7.81 (d, J=2.0 Hz, 1H), 7.29 (dd, J=8.1, 2.1 Hz, 1H), 6.93 (d, J=8.1 Hz, 1H), 5.29-5.25 (m, 1H), 4.98 (d, J=1.2 Hz, 1H), 2.86-2.76 (m, 2H), 2.65-2.57 (m, 2H), 1.87-1.84 (m, 1H), 1.60 (s, 3H).