Light, medium, and heavy fluorous triarylphosphines exhibit comparable reactivities to triphenylphosphine in typical reactions of triarylphosphines

The relative reactivities of triphenylphosphine (PPh3) and three fluorous triarylphosphines [(p-R-F(CH2)(2)C6H4)(n)PPh3-n, where n = 1-3] have been compared in internal competition experiments. Product ratios were determined by P-31 NMR spectroscopy. The four phosphines have about the same reactivities in oxidation, alkylation, and Staudinger reactions and give comparable yields in a preparative Mitsunobu reaction. Previously observed rate and yield differences in Staudinger reactions of the fluorous phosphines are attributed to solubility effects, not reactivity differences. A light fluorous phosphine [(p-C8F17(CH2)(2)C6H4)PPh2] outperforms a commercially available resin-bound phosphine in a competitive benzylation experiment by a factor of about 4.