A solution of [(4-bromo-2-methoxyphenyl)ethynyl](trimethyl)silane (1.426 g, 5.035 mmol) in dry THF (25 mL) was degassed and backfilled with argon for three times. Pd2(dba)3 (230.5 mg, 0.252 mmol) and 2-dicyclohexylphosphino-2-(N,N′-dimethylamino)biphenyl (79.3 mg, 0.201 mmol) were added under argon atmosphere and the mixture was degassed and backfilled with argon for three times. Then 1 M LiHMDS in THF (12.1 mL, 12.084 mmol) and N-methylpiperazine (1.34 mL, 1.21 g, 12.083 mmol) were added by a syringe and the mixture was degassed and backfilled with Argon for three times. The reaction mixture was heated to reflux for 1 h. After cooling to room temperature the reaction mixture was filtered on a pad of celite washing with THF (200 mL). The filtrate was evaporated under vacuum and the black oil so obtained was purified by chromatography on silica gel (DCM/MeOH 9/1) to afford the title compound as a brownish solid (1.042 g, 68.4%).
