Acetonitrile (23 ml) was added to a mixture of triphenylphosphine (6.7 g, 25.7 mmole) and Part (6) compound (4.6 g, 21.2 mmole). The solution was heated at gentle reflux under magnetic stirring for 30 hours. Toluene (46 ml) was then added and the reaction was brought to reflux for a brief period. The reaction was allowed to cool to 5° C. and kept overnight. The resulting white precipitates were collected, washed with cold acetonitrile/toluene (1/2), and dried in a heated vacuum oven (60° C.~5 mmHg) to give the title bromide (9.8 g, 20.4 mmole, 96.5%) as white solid.
