Methanesulfonyl chloride → 2-(2-Benzyloxycarbonylamino-ethyl)-4-(tert-butyl-dimethyl-silanyloxy)-3-methanesulfonyloxy-pyrrolidine-1-carboxylic acid tert-butyl ester

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Reaction Conditions

Reaction Steps

A solution containing crude 8 (500 mg, 1.01 mmol) in DCM (15 mL) was cooled to 0° C. DIPEA (261 mg, 2.02 mmol) was added followed by the addition of MsCl (117 mg, 1.02 mmol) and DMAP (13 mg, 0.1 mmol). After 2 h, the reaction mixture was warmed to ambient temperature, diluted with DCM, washed successively with 1M HCl and brine, dried over anhydrous Na2SO4, filtered, and concentrated to afford 578 mg (quant.) of crude 9 as a tan-colored foam which was used without further purification. 1H NMR (CDCl3, 300 MHz), mixture of rotomers: δ7.35 (m, 5H), 5.90 (m, 1H), 5.10 (m, 2H), 4.67 (m, 1H), 4.40 (m, 1H), 4.11 (m, 2H), 3.94 (m, 0.5H), 3.80 (m, 0.5H), 3.74 (app dd, J=12.2, 5.0 Hz, 1H), 3.51 (m, 0.5H), 3.31 (m, 0.5H), 3.02 (s, 3H), 1.96 (m, 0.5H), 1.85 (m, 0.5H), 1.46 (s, 9H), 0.88 (s, 9H), 0.05 (s, 6H) ppm. Mass spectrum, m/z [595.2] (M+Na)+.

Provenance & Evidence