(Diethylamino)sulfur trifluoride → 1,4-Dibenzyl-2-(fluoromethyl)piperazine

Participants

Reaction Conditions

Reaction Steps

To a stirred solution of diethylaminosulfur trifluoride (0.89 g, 5.53 mmol) in DCM (4 mL) at −78° C. under nitrogen was added a solution of (1,4-dibenzyl-piperazin-2-yl)-methanol (1.364 g, 4.61 mmol) in DCM (6 mL), dropwise over 0.2 h (internal temperature <−65° C.). Resulting solution was stirred at −78° C. for 1 h then warmed slowly to 20° C. and stirred thus for 16 h. The mixture was cooled in an ice-methanol bath then ice was added with stirring. The mixture was poured into saturated aqueous NaHCO3 (100 mL) and extracted with DCM (3×30 mL). The combined organic extracts were dried (Na2SO4) and evaporated in vacuo to give an oil. Chromatography (SiO2; gradient elution with 0-25% diethyl ether in 40-60 petroleum ether) gave the title compound (0.471 g) as an oil. 1H NMR (CDCl3): 7.38-7.23 (10H, m), 4.93-4.64 (1H, m), 4.55 (1H, ddd), 4.03 (1H, d), 3.52 (3H, d), 2.91 (1H, d), 2.84-2.64 (2H, m), 2.56 (1H, s), 2.48-2.21 (3H, m).

Provenance & Evidence