F-Pyridinium salt is the fluorous analog to 2-halopyridinium salts that have been widely used for the activation of carboxylic acids to form esters, amides, and lactones.  Pyridinium salts are efficient coupling reagents for peptide synthesis and exhibit faster formation of coupling products than other commonly used coupling reagents including BOP-Cl, PyBroP, and PyClU.  The fluorous version is especially useful with HOBt to rapidly form activated acid as the corresponding benzotriazoyl ester (1).  The pyridone by product is easily removed from the desired product by F-SPE.

1. Nagashima, T.; Lu, Y.; Petro, M. J.; Zhang, W. Tetrahedron Lett. 2005, 46, 6585-6588.

2. Matsugi, M., Hasegawa, M., Sadachika, D., Okamoto, S., Tomioka, M., Ikeya, Y., Masuyama, A., Mori, Y., Tetrahedron Letters 2007, DOI: 10.1016/j.tetlet.2007.03.173