4-Toluenesulfonyl chloride → 1-tert-Butyl 2-methyl (2S,4R)-4-[(4-methylbenzene-1-sulfonyl)oxy]pyrrolidine-1,2-dicarboxylate

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Reaction Steps

To a solution of methyl (2S,4R)—N-tert-butoxycarbonyl-4-hydroxy-2-pyrrolidinecarboxylate (4.68 g, 19.1 mmol) in DCM (47 mL) at RT was added DIPEA (3.66 mL, 21.0 mmol) and 4-dimethylaminopyridine (233 mg, 1.91 mmol) followed by p-toluenesulfonyl chloride (3.82 g, 20.1 mmol). The reaction mixture was stirred at RT overnight, washed with 1N HCl (2 mL), saturated sodium bicarbonate (2 mL), and brine (2 mL), dried over sodium sulfate, filtered and concentrated to give a yellowish oil, which was purified by silica gel chromatography (80 g silica, 0-100% EtOAc/Hexanes). Desired fractions were combined and concentrated to give the title intermediate (1.74 g, 23% yield) as a colorless oil.

Provenance & Evidence