A solution of tert-butyl(4-chloro-3-iodophenoxy)dimethylsilane (Preparation 53, 102 mg, 0.28 mmol), 2-(4-(ethylsulfonyl)-2-methoxyphenyl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (Preparation 21) (90 mg, 0.28 mmol) and aqueous caesium carbonate solution (1M, 0.55 mL, 0.55 mmol) in dioxane (4 mL) was degassed with nitrogen for 10 minutes, followed by the addition of 1,1′-bis(diphenylphosphino)ferrocene-palladium(II)dichloride (11.0 mg, 0.014 mmol). The resulting mixture was heated at 100° C. for 3 hours and then cooled to room temperature. The mixture was partitioned between water (15 mL) and EtOAc (15 mL), the aqueous layer then extracted with EtOAc (2×15 mL). The organic layers were combined and washed with brine (25 mL), dried over MgSO4 and then concentrated in vacuo. 4M HCl in dioxane (4 mL) was added to the residue, and the mixture stirred at room temperature for 40 hours. After concentration in vacuo, NH3 solution (7M in MeOH, 2 mL) was added to the residue, and the mixture re-concentrated in vacuo. The residue was purified by silica gel column chromatography eluting with cyclohexane/EtOAc 70:30 to afford the title compound as yellow gum in 72% yield, 65 mg.
