(Diethylamino)sulfur trifluoride → (2R,5R)-4-Benzyl-5-fluoromethyl-2-methyl-piperazine-1-carboxylic acid tert-butyl ester

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Reaction Conditions

Reaction Steps

To a stirred solution of diethylaminosulfur trifluoride (0.32 mL, 0.393 g, 2.44 mmol) in DCM (2 mL) at −78° C. under nitrogen was added a solution of (2R,5R)-4-benzyl-5-hydroxymethyl-2-methyl-piperazine-1-carboxylic acid tert-butyl ester (0.651 g, 2.03 mmol) in DCM (6 mL). Mixture was stirred at −78° C. for 0.5 h then at 20° C. for 3 h. Mixture was poured into saturated aqueous sodium hydrogen carbonate (100 mL) and ice (20 g) then extracted with DCM (3×50 mL). Combined organic extracts were dried (Na2SO4) and evaporated in vacuo to give an oil. Chromatography (SiO2; gradient elution with 0-40% Et2O in 40-60 petroleum ether) gave the title compound (0.393 g) as an oil. MS: [M+H]+=323.

Provenance & Evidence