[Br:1][C:2]1[C:11]([CH3:12])=[CH:10][C:9]2[C:8]([CH3:14])([CH3:13])[CH:7]=[CH:6][C:5]([CH3:16])([CH3:15])[C:4]=2[CH:3]=1.S(=O)(O)[O-:18].[Na+].[OH2:22]>N1C=CC=CC=1.[Os](=O)(=O)(=O)=O>[Br:1][C:2]1[C:11]([CH3:12])=[CH:10][C:9]2[C:8]([CH3:14])([CH3:13])[C@@H:7]([OH:22])[C@@H:6]([OH:18])[C:5]([CH3:16])([CH3:15])[C:4]=2[CH:3]=1To a solution of 9.41 g (33.7 mmol) of 2-bromo-3,5,5,8,8-pentamethyl-5,8-dihydronaphthalene in 110 ml pyridine was added 8.65 g (34.0 mmol) osmium tetroxide under an atmosphere of nitrogen. After stirring at room temperature for 18 hours, 17.3 g (166 mmol) of sodium bisulfite in 110 ml water was added. After 2 hours the resulting solution was partitioned between ethyl acetate and aqueous hydrochloric acid. The organic layer was washed with water, washed with brine, dried over anhydrous sodium sulfate, and concentrated in vacuo. The crude material was purified by flash chromatography with elution with 30% ethyl acetate/hexane to yield 7.97 g (75%) of 2-bromo-cis-6,7-dihydroxy-3,5,5,8,8-pentamethyl-5,6,7,8-tetrahydronaphthalene as a white solid (M+=312).
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