Methanesulfonyl chloride → 1-tert-Butyl 2-methyl (2S,4R)-4-((methanesulfonyl)oxy)pyrrolidine-1,2-dicarboxylate

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Reaction Steps

Add methanesulfonyl chloride (1.56 mol, 179 g) drop wise to a solution of (2S,4R)-4-hydroxy-pyrrolidine-1,2-dicarboxylic acid 1-tert-butyl ester 2-methyl ester (0.65 mol, 160 g) in pyridine (600 mL) at 0° C. under a nitrogen atmosphere. Upon complete addition, warm the reaction mixture to room temperature and stir for 2 h. Dilute the reaction mixture with dichloromethane, wash with 0.1 N hydrochloric acid solution and saturated sodium bicarbonate solution. Dry the organic layer over anhydrous sodium sulfate, filter, and concentrate under vacuum to obtain the title compound (185 g, 91%) as a thick oil. ES-MS m/z 324.1 [M+1]+, 224.0 [M−Boc]+.

Provenance & Evidence