TRIPHENYLPHOSPHINE DIBROMIDE

Chemical properties

light yellow to light pink crystalline powder

The Uses of TRIPHENYLPHOSPHINE DIBROMIDE

Triphenylphosphine dibromide is used as a reagent for conversion of aldoximes into nitriles. It acts as a reagent for cleavage of acetals. It reacts with amines to give iminophosphoranes. Further, it serves as a reagent in the preparation of alkyl and aryl bromides from alcohols and phenols without rearrangement.

The Uses of TRIPHENYLPHOSPHINE DIBROMIDE

The SM (6.8 g, 0.036 mol) was taken up in DCM (275 mL) and treated with PPh3 (10.36 g) and CBr4 (13.1 g). The reaction mixture was stirred at RT for 90 min, after which time the solvent was concentrated to a volume of about 50 mL (precipitation occurs). The slurry was added to a pad of silica gel eluting with 20% EtOAc/hexane. Fractions containing the product (least polar) were combined and concentrated to provide the product as a viscous syrup. [6.2 g, 69%]

What are the applications of Application

Triphenylphosphine dibromide is Used in the preparation, with minimal/no rearrangement, of alcohols and phenols to alkyl and aryl bromides

Purification Methods

It recrystallises from MeCN/Et2O. Although it has been recrystallised from EtOH, this is not recommended as it converts alcohols to alkyl bromides. It deteriorates on keeping, and it is best to prepare it afresh. [Anderson & Freenor J Am Chem Soc 86 5037 1964, Horner et al. Justus Liebigs Ann Chem 626 26 1959, Beilstein 16 III 864.]