Reactivity of perfluoro-n-alkyl radicals with reluctant substrates. Rates of addition to RFCH2CH=CH2 and RFCH=CH2

Absolute Rates of Intermolecular Carbon−Hydrogen Abstraction Reactions by Fluorinated Radicals

“…Thus rate constants for hydrogen abstraction by perfluoroalkyl radicals from relatively electropositive atoms such as Sn, Si, or even carbon are much larger than those of the analogous alkyl radicals. For example, the rate constants for hydrogen abstraction from n -Bu 3 SnH and Et 3 SiH by n -R f • are 85 and 714 times larger, respectively, than by n -R • . − With a preliminary indication of molar rate constants in the range of 10 4 −10 5 M -1 s -1 for hydrogen transfer from relatively good C−H donors such as tetrahydrofuran (THF), we considered it important to evaluate and quantitate the bimolecular C−H donor ability of a broad range of functionalized organic compounds having C−H bonds in a variety of molecular environments. In commercial polymerizations, H-transfer from C−H bonds of surfactants and initiators can be the main source of polymer inhibition or low molecular weight product as a result of terminating chain transfer .…”

Synthetically useful carbon–carbon and carbon–sulphur bond construction mediated by carbon- and sulphur-centred radicals in water and aqueous media

“…12 It has been observed in organic solvents, that the rates of addition of R f N radicals to alkenes correlate with the alkene IP (ionization potential) (which reflects the HOMO energies). 13 Indeed, the major transition state orbital interaction for the addition of the highly electrophilic R f N radical to an alkene is that between the SOMO of the radical and the HOMO of the alkene. Thus, the rates of R f N radical addition to electron deficient alkenes are slower than those of addition to electron rich alkenes (as observed in organic solvents).…”

“…This seems to indicate that the reactivities of electron rich and electron deficient alkenes towards R f N radicals in water are levelled off. 13 A tandem radical addition-oxidation sequence which converts alkenyl silanes into ketones has been elegantly described by Oshima et al 14 When 2-silyl-1-alkenes (carbonyl synthons) are made to react with an excess of Et 3 B (2 equiv.) in air, methyl ketones are afforded as major products as shown in Scheme 1 below.…”

Visible light-catalyzed fluoroalkylation reactions of free aniline derivatives

“…The electron-rich nature of aminoaromatic compounds and the electrophilic character of fluoroalkyl R F radicals allow for a special match in substitution reactions [11][12][13]. This reactivity marriage has encouraged profuse studies, and come up with different protocols and alternative approaches to substitute free aniline derivatives with R F moieties.…”