Dissolve zinc (II) bromide (313 mg, 1.20 mmol) in tetrahydrofuran (2.5 mL) and treat with triethylamine (0.64 mL, 4.80 mmol). After 4 min add N-(5-bromo-2-fluorobenzyl)methanesulfonamide (282 mg, 1.00 mmol), (prepared as described in PREPARATION 35), trimethylsilylacetylene (0.30 mL, 2.12 mmol), and tetrakis(triphenylphosphine)palladium (0) (58 mg, 0.050 mmol) to the reddish solution. Heat to 60° C. in a sealed tube overnight, cool to room temperature and filter through diatomaceous earth with ethyl acetate. Concentrate the filtrate and purify the residue by silica gel chromatography, eluting with 75:25 hexanes:ethyl acetate, to give the title compound as a white crystalline solid (220 mg, 74%).
