Potassium tert-butoxide → HCID 86700852, compound

To a solution of triphenylphosphine methoxymethane chloride (3.51 g, 10.24 mmol) in tetrahydrofuran (20 ml) under nitrogen at room temperature, was added potassium t-butoxide (1.149 g, 10.24 mmol). The reddish solution was stirred at room temperature for 90 minutes. Then a solution of 6-bromo-1-(4-chloro-phenyl)-2-oxa-bicyclo[2.2.2]octane-4-carbaldehyde (2.25 g, 6.83 mmol) in tetrahydrofuran (6 ml) was added to the reaction mixture. The reaction mixture was stirred at room temperature for 10 minutes and then quenched with water (2 ml). The mixture was partitioned between brine (15 ml) and ethyl acetate (60 ml). The aqueous layer was extracted with ethyl acetate (2×30 ml) and the combined organic extracts were washed with brine, dried over Na2SO4, and concentrated. The residue was purified by flash chromatography (heptanes/acetone 2/1) to afford the cis and trans mixtures of 6-bromo-1-(4-chloro-phenyl)-4-(2-methoxy-vinyl)-2-oxa-bicyclo[2.2.2]octane (2.32 g, 95%) as colorless oil. 1H NMR (400 MHz, CHLOROFORM-d) δ ppm 1.74-2.99 (m, 6H) 3.54 (3.89 (m, 4H) 3.91-6.36 (m, 5H) 7.28-7.43 (m, 4H).