Perfluoroalkylations of Carbanions with (Perfluoroalkyl)phenyliodonium Triflates (FITS Reagents)

FITS reagents reacted with primary alkylmagnesium halides in THF at −78 °C to give the corresponding perfluoroalkyl(Rf)-alkanes in moderate to good yields. But an alkyl-lithium or -copper gave a poor yield of the Rf-product. The reaction of FITS with secondary or tertiary alkylmagnesium halides resulted in low yields of the products. Alkynyl-lithiums or -magnesium halides produced Rf-alkynes in favorable yields. The reaction with aryl or vinylmagnesium halide was complex and the yields of Rf derivatives were low. FITS also reacted smoothly with enolate anions of active methylene compounds such as 2-methyl-1,3-cyclopentanedione, ethyl 2-methylacetoacetate, and ethyl 2-oxocyclopentanecarboxylate in a polar solvent to afford O- and C-perfluoroalkylation products in moderate yields, ratios O-/C-Rf products depending on the reaction temperature. Anions of diethyl 2-methylmalonate and 2-nitropropane afforded C-Rf-compounds only.