Hydrochloric Acid → (S)-3-(Toluene-4-sulfonyloxy)-pyrrolidine-1-carboxylic acid tert-butyl ester

Participants

Reaction Steps

To a 0° C. solution of (S)-3-hydroxy-pyrrolidine-1-carboxylic acid tert-butyl ester (8.5 g, 45.4 mmol), triethylamine (9.47 ml, 68.1 mmol) and dimethylaminopyridine (0.55 g, 4.5 mmol) in CH2Cl2 (150 ml) was added portionwise p-toluenesulfonyl chloride (9.52 g, 49.9 mmol). After 48 hours stirring at room temperature, reaction mixture was acidified to pH 1 with 1N HCl and aqueous phase was extracted with CH2Cl2. Combined organic phases were washed with 1N HCl and H2O, dried over Na2SO4 and concentrated. The residue was chromatographed over silica gel (hexane-ethylacetate 9:1 then 8:2 then 1:1) to provide (S)-3-(toluene-4-sulfonyloxy)-pyrrolidine-1-carboxylic acid tert-butyl ester (13.1 g, 87%) as a slightly yellow oil, MS: m/e=268.1 (M-OtBu) and [α]D20=+17.55° (c=3.33, diethylether).

Provenance & Evidence