Acid C₂F₅–Togni reagent

CAS 1401714-42-8, Cat. No EN300-23000638
Reagent for fluoroalkylation

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1-(1,1,2,2,2-Pentafluoroethyl)-1,2-benziodoxol-3(1H)-one (acid C₂F₅–Togni reagent) is a hypervalent iodine(III) compound structurally related to Togni’s trifluoromethylating reagents. It serves as a convenient and stable source of the pentafluoroethyl (C₂F₅) radical. In ligand-free nickel catalysis¹, it enables direct C–H pentafluoroethylation of arenes and heteroarenes. Electron-rich substrates such as trimethoxybenzene and pyrimidines give high yields of 75–97%, while pyrroles and indoles react in moderate to good yields of 30–73%. The reaction shows good tolerance of halogens and Boc-protected substrates, with regioselectivity governed by electronic and steric effects. In the hydroxylamine-mediated protocol², the reagent is used for radical addition–elimination on alkenes, producing vinyl–C₂F₅ products. A broad range of substrates, including styrenes, disubstituted alkenes, 1,2-dihydronaphthalenes, and 1,3-dienes, give yields of 68–99%. This method delivers excellent E/Z stereoselectivity, typically greater than 20:1, and tolerates a wide array of functional groups, including halides in all positions, nitro groups, esters, dimethoxy, and dimethyl substituents, and heteroaryl systems.

Synonyms: 1-(1,1,2,2,2-pentafluoroethyl)-1,2-benziodoxol-3(1H)-one; 1,2-benziodoxol-3(1H)-one, 1-(1,1,2,2,2-pentafluoroethyl)-; 1-(1,1,2,2,2-pentafluoroethyl)-3H-1lambda3,2-benziodaoxol-3-one; C₂F₅–Togni reagent