HCID 86700852, Verbindung → HCID 86700854, Verbindung

To a stirred solution of the cis and trans mixtures of 6-bromo-1-(4-chloro-phenyl)-4-(2-methoxy-vinyl)-2-oxa-bicyclo[2.2.2]octane (1.7 g, 4.75 mmol) in dichloromethane (12 ml) and tetrahydrofuran (25 ml) at room temperature, was portionally added pyridinium chlorochromate (3.07 g, 14.26 mmol). The reaction mixture was stirred at room temperature for 2 hours. More pyridinium chlorochromate (2.05 g, 9.51 mmol) was added, and the mixture was stirred for another 60 hours at room temperature. The mixture was filtrated and the filtrate was concentrated, and diluted with ethyl acetate (100 ml). The organic phase was washed with water, brine and dried over Na2SO4, and concentrated. The residue was purified by flash chromatography (heptanes/acetone 2/1) to afford [6-bromo-1-(4-chloro-phenyl)-2-oxa-bicyclo[2.2.2]oct-4-yl]-acetic acid methyl ester (1.08 g, 61%) as colorless oil. 1H NMR (400 MHz, CHLOROFORM-d) δ ppm 1.69-1.79 (m, 1H) 1.87-1.98 (m, 1H) 2.01-2.11 (m, 1H) 2.14 (s, 2H) 2.23-2.30 (m, 1H) 2.52-2.63 (m, 1H) 2.75-2.87 (m, 1H) 3.62 (s, 3H) 3.84 (dd, J=10.11, 2.65 Hz, 2H) 4.19-4.29 (m, 1H) 7.23 (d, J=8.80 Hz, 2H) 7.33 (d, J=8.80 Hz, 2H).