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. 

Solvent effect on TPPO precipitation with CaBr2

參考資料

Org. Process Res. Dev. 2022；https://doi.org/10.1021/acs.oprd.2c00104。