[Br:1][C:2]1[CH:7]=[C:6]([N+:8]([O-:10])=[O:9])[CH:5]=[C:4]([CH3:11])[C:3]=1[C@H:12]([OH:15])[CH2:13][OH:14].N1C=CC=CC=1.[C:22](Cl)([C:24]([CH3:27])([CH3:26])[CH3:25])=[O:23].C([O-])(O)=O.[Na+]>C(Cl)Cl>[C:22]([O:14][CH2:13][C@H:12]([C:3]1[C:4]([CH3:11])=[CH:5][C:6]([N+:8]([O-:10])=[O:9])=[CH:7][C:2]=1[Br:1])[OH:15])(=[O:23])[C:24]([CH3:27])([CH3:26])[CH3:25]To a suspension of (S)-1-(2-Bromo-6-methyl-4-nitrophenyl)ethane-1,2-diol (17.0 g, 61.6 mmol) in DCM (435 mL) at 0° C. was added pyridine (18.6 g, 235.4 mmol) and PivCl (13.4 g, 110.8 mmol) slowly. After stirring at 0° C. for 5 min, the system was raised to room temperature and stirred at this temperature for 5 h. TLC showed the reaction was complete. The reaction mixture was treated with saturated aqueous NaHCO3 (500 mL), and the resulting system was extracted with DCM (2×200 mL). The combined organic layer was dried over anhydrous Na2SO4, filtered, concentrated in vacuum, and purified by silica gel column (Petroleum Ether:EtOAc (30:1)) to afford (S)-2-(2-Bromo-6-methyl-4-nitrophenyl)-2-hydroxyethyl pivalate (17 g, 77%) as yellow solid. 1H-NMR: 400 MHz, (CDCl3) δ: 8.28 (s, 1H), 8.00 (d, J=2.0 Hz, 1H), 5.70-5.66 (m, 1H), 4.58-4.53 (m, 1H), 4.31-4.26 (m, 1H), 2.84 (d, J=5.6 Hz), 2.68 (s, 3H), 1.22 (s, 9H).
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