7-Bromo-1-benzofuran → Tert-butyl 4-(7-benzo[b]furanyl)piperazine-1-carboxylate

Participants

Reaction Conditions

Reaction Steps

7-bromobenzofuran (500 mg, 2.54 mmol), tert-Butyl 1-piperazinecarboxylate (473 mg, 2.54 mmol), Tris(dibenzylideneacetone)dipalladium(0) (116 mg, 0.13 mmol), 2-Dicyclohexylphosphino-2',4',6'-tri-iso-propyl-1,1'-biphenyl (121 mg, 0.25 mmol) and sodium t-butoxide (0.464 mL, 5.33 mmol) were heated in toluene (2 mL) to 100 °C for 2h. The mixture was allowed to cool. Ethylacetate was added and the mixture was filtered through Celite. The filtrate was concentrated and redissolved in ethylacetate. The organic mixture was washed with satd. aqueous Na2CO3 and brine. The organic phase was separated, dried over Na2CO3, filtered and the solvent removed by rotary evaporation. The crude product was added to a silica gel column and was eluted with 0-2% MeOH in DCM and to a second silica gel column eluted with 0-100% EtOAc in heptane. The collected fractions were combined to yield tert-butyl 4-(benzofuran-7-yl)piperazine-1-carboxylate (560 mg, 73.0 %). 1H NMR in CD3OD is consistent with desired product MS (m+1) = 303.1. HPLC Peak RT = 5.99 minutes is product. Purity = 98%.

Provenance & Evidence