| 15845013 |
Curran DP, Wang X, Zhang Q: Light, medium, and heavy fluorous triarylphosphines exhibit comparable reactivities to triphenylphosphine in typical reactions of triarylphosphines. J Org Chem. 2005 Apr 29;70(9):3716-9.
[reaction: see text] The relative reactivities of triphenylphosphine (PPh (3)) and three fluorous triarylphosphines [(p-R (F)(CH (2))(2) C (6) H (4))(n) PPh (3)(-)(n), where n = 1-3] have been compared in internal competition experiments. Product ratios were determined by (31) P 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-C (8) F (17)(CH (2))(2) C (6) H (4)) PPh (2)] outperforms a commercially available resin-bound phosphine in a competitive benzylation experiment by a factor of about 4. |
81(1,1,1,1) |