Iodine(III) reagents of the type ArIL2 are useful oxidants in inorganic and organic chemistry. Their properties can be tuned by changing the ligand L and/or the substitution pattern on the aryl ring. A para-nitro group, for example, can enhance the oxidative capacity, as can triflate (OTf) ligands. As a result, NO2–C6H4–I(OTf)2 is highly reactive.
Jason L. Dutton, La Trobe University, Melbourne, Australia, and colleagues aimed to further enhance the reactivity of ArIL2-type compounds, using bistriflimide (NTf2, or N(SO2CF3)2) as the ligand instead of triflate. The team used TMS (trimethylsilyl) metathesis and reacted NO2–C6H4–IF2 or NO2–C6H4–I(OTFA)2 (OTFA = trifluoracetoxy) with TMS-NTf2 in CDCl3. This reaction gave the desired NO2–C6H4–I(NTf2)2, which was confirmed by NMR spectroscopy and X-ray crystallography, as well as TMS-F or TMS-OTFA.
The researchers found that NO2–C6H4–I(NTf2)2 can be used to perform oxidation reactions for which ArI(OTf)2-type compounds are not reactive enough, such as the oxidation of 3-methylcyclohexene to toluene. The team used theoretical studies to gauge the oxidation potential of NO2–C6H4–I(NTf2)2 and similar compounds. They found that Ar–I(NTf2)2 is the
most oxidizing class of known ArIL2-type compounds. They also propose that Ar–I(NTf2)2 might be the compound class that represents the limit of oxidative capacity for ArIL2-type compounds in practical uses.
- ArI(NTf2)2: the boundary of oxidative capacity for ArIL2?,
Lachlan Barwise, Jason D. Bennetts, Keith F. White, Jason L. Dutton,
Chem. Commun. 2023.