Easy Removal of Triphenylphosphine Oxide from Reaction Mixtures by Precipitation with CaBr2

A reliable and scalable purification procedure for the easy removal of triphenylphosphine oxide by complexation with CaBr2 in ethereal solvents or toluene was developed. The resulting insoluble precipitated complex was easily eliminated from crude reaction mixtures in high yields by filtration without the need of purification by column chromatography. The compatibility of this procedure with different organic solvents, salts, filtration aids, packing materials, and several molecules containing most common organic functional groups was examined to explore the scope and limitations of this method. Additionally, precipitation of TPPO by complexation with other halide salts was also explored.