Triethylamine → 4-(4-Trimethylsilanylethynyl-benzenesulfonyl)-piperazine-1-carboxylic acid tert-butyl ester

Participants

Reaction Conditions

Reaction Steps

Trimethylsilylacetylene (0.70 mL, 4.94 mmol) and triethylamine (2.80 mL, 19.74 mmol) were added to a stirred solution of 4-(4-bromo-benzenesulfonyl)-piperazine-1-carboxylic acid tert-butyl ester (1.00 g, 2.468 mmol) in dry dichloromethane (12 mL), then the reaction mixture was degassed with argon for 30 minutes at room temperature. To the reaction mixture were added Pd(PPh3)2Cl2 (0.173 g, 0.25 mmol) and CuI (0.047 g, 0.25 mmol), then the reaction mixture was heated at 50° C. for 14 hours under an argon atmosphere. The reaction mixture was cooled to room temperature and then concentrated in vacuo to yield a crude residue, which was dissolved in dichloromethane (20 mL) and washed with water (2×5 mL) and brine (5 mL). The organic phase was dried over anhydrous sodium sulfate and concentrated in vacuo to afford a black colored crude product, which was finally purified using silica gel (100-200 mesh) column chromatography (2:23 ethyl acetate-hexanes to 2:18 ethyl acetate in hexanes) to furnish 1.20 g (80%) of 4-(4-trimethylsilanylethynyl-benzenesulfonyl)-piperazine-1-carboxylic acid tert-butyl ester as a brown solid. MS cald. for C20H30N2O4SSi [(M+NH4)+] 440, obsd. 440.0.

Provenance & Evidence