Triphenyl thioborate

Alternate Names phenyl thioborate tris(phenylthio)borane. Physical Data pale yellow solid mp 140-143 °C bp 196°C/0.1mmHg.  

Preparative Methods can be made from boron triiodide and diphenyl disulfide from thiophenol and boron trichloride from (phenylthio)borane trimer and thiophenol or from boron trisulfide and thiophenol.  

Purification recrystallize from benzene or distill in vacuo. Handling, Storage, and Precautions sensitive to moisture and should be stored in a desiccator. Can be weighed out quickly in air, if humidity is low, but best handled in a dry box.  

Conversion of Esters and a,/9-Unsaturated Esters into Phenylthio Esters. Esters are converted into phenylthio esters by heating with phenyl thioborate in refluxing xylene (140 °C) (eq 1), but the same transformation can be done at room temperature with phenyl thioaluminate. With the aluminum reagent, a, -unsaturated esters give products contaminated with the )S-(phenylthio) ester, but the boron reagent does not suffer from this disadvantage (eq 2). 

Merck Sharp Dohme Research Laboratories, Harlow, UK 

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