To a magnetically stirred solution of 0.206 g (0.52 mmol) of the product of step A dissolved in 2 mL methylene chloride was added 0.162 g (0.62 mmol) of triphenylphosphine followed by 0.205 g (0.62 mmol) of carbon tetrabromide at 0° C. The reaction mixture was held at 0° C. for 10 minutes, then allowed to warm to room temperature and stirred for 2.5 hours. The reaction mixture was then concentrated in vacuo and the residue was applied to a silica gel flash chromatography column and eluted with 15% EtOAc-hexane. The purified fractions were combined, evaporated and dried in vacuo to afford 0.220 g (92%) yield of the title compound.
