General procedure for the synthesis of 1,1,4,4-tetramethyl-1,2,3,4-tetrahydronaphthalene from 2,5-dichloro-2,5-dimethylhexane and benzene: 2,5-dichloro-2,5-dimethylhexane (300 mg, 1.64 mmol, 1 eq.) was dissolved in dry benzene (25 mL). To this solution was added anhydrous aluminum trichloride (AlCl3, 22.0 mg, 0.164 mmol, 0.1 eq.) and the reaction mixture was stirred under reflux conditions for 16 hours. Upon completion of the reaction, the reaction was quenched with 3M hydrochloric acid (5 mL) and extracted with hexane (10 mL × 3). The organic layers were combined, washed with saturated saline, dried over anhydrous sodium sulfate (Na2SO4), filtered and concentrated in vacuum. The crude product was purified by fast column chromatography (100% hexane as eluent) to afford 1,1,4,4-tetramethyl-1,2,3,4-tetrahydronaphthalene (309 mg, 91% yield) as a colorless oil. The product was characterized as follows: 1H NMR (500 MHz, CDCl3) δ 1.33 (s, 12H), 1.74 (s, 4H), 7.16-7.19 (m, 2H), 7.34-7.36 (m, 2H, J = 2 Hz and 8.4 Hz); 13C NMR (500 MHz, CDCl3) δ 31.9, 34.2, 35.1, 125.5, 13C NMR (500 MHz, CDCl3) δ 31.9, 34.2 35.1, 125.5, 126.5, 144.8.
