[C:1]([C@@H:5]1[O:9][C:8](=[O:10])[C@H:7]([CH3:11])[O:6]1)([CH3:4])([CH3:3])[CH3:2].[Br:12]N1C(=O)CCC1=O.C(OOC(=O)C1C=CC=CC=1)(=O)C1C=CC=CC=1>C(Cl)(Cl)(Cl)Cl>[Br:12][C@:7]1([CH3:11])[O:6][C@@H:5]([C:1]([CH3:4])([CH3:2])[CH3:3])[O:9][C:8]1=[O:10]In 500 ml of carbon tetrachloride, 48.0 g of the (2S,5S)-2-tert-butyl-5-methyl-1,3-dioxolan-4-one obtained in Step 1 was dissolved. To the resulting solution, 54.0 g of N-bromosuccinimide and 1.0 ml of benzoyl peroxide were added, and the solution was refluxed for 2 hours. After the reaction solution was left to have cooled, insolubles were separated by filtration and the filtrate was successively washed with an aqueous 10% sodium thiosulfate solution, a saturated aqueous sodium hydrogencarbonate solution and a saturated brine. From the filtrate thus washed, the carbon tetrachloride was evaporated under reduced pressure, and the resulting residue was recrystallized from hexane to obtain 70.5 g of (2S,5S)-5-bromo-2-tert-butyl-5-methyl-1,3-dioxolan-4-one.
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