A mixture of 2-bromo-1-methyl-4-(propylsulfonyl)benzene (Intermediate 37; 14.86 g, 53.6 mmol), tert-butyl(4-chloro-2-ethynylphenoxy)acetate (Intermediate 3, 13.00 g; 48.7 mmol), dichlorobis(triphenylphosphine)palladium(II) (1.37 g; 1.95 mmol) and piperidine (14.5 mL) was heated at 70° C. for 18 hours. The reaction mixture was taken up in EtOAc, washed twice with ammonium chloride and once with brine. The organic phase was dried over MgSO4, filtered and concentrated to dryness affording a crude, which was purified by flash column chromatography (silica), eluting with cyclohexane containing increasing amounts of EtOAc. The compound thus obtained as a brown sticky solid was recrystallized twice from EtOAc/petroleum ether to afford the title compound as a beige solid.
