Water → (R)-Methyl 2-(2-chlorophenyl)-2-(4-nitrophenylsulfonyloxy)acetate

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Reaction Steps

(R)-Methyl o-chloromandelate (98.4 g, 0.49 mol, ee=99%) was dissolved in 500 ml of anhydrous dichloromethane, and then 91 ml of triethylamine (0.65 mol) and a catalytic amount of DMAP were added. 120 g (0.54 mol) of p-nitrophenylsulfonyl chloride was dissolved in 500 ml of anhydrous dichloromethane, which was added dropwise into the reaction solution at 0° C., and reacted for 4-5 hrs at 0° C. Water (500 ml) was added to the reaction solution and the layers were separated. The aqueous phase was extracted with dichloromethane (150 ml×3), and the organic phases were combined and dried, and dichloromethane was evaporated under reduced pressure to afford 206.5 g of a crude product as a dark red oil, which was recrystallized in methanol to obtain 154.5 g of a solid product (II-1). Yield 82%. 1H-NMR (300 MHz, CDCl3) δ 3.57 (s, 3H), 6.39 (s, 1H), 7.21-7.39 (m, 4H), 8.07 (d, 2H, J=8.9 Hz), 8.30 (d, 2H, J=8.9 Hz); ESI-MS m/z 408.0 [M+Na]+.

Provenance & Evidence