Togni reagent II (1-trifluoromethyl-1,2-benziodoxol-3(1H)-one) is a chemical compound used in organic synthesis for direct electrophilic trifluoromethylation.

[1][2] Synthesis, properties, and reactivity of the compound were first described in 2006 by Antonio Togni and his coworkers at ETH Zurich.

The target compound can then be obtained by acylation with acetic anhydride and subsequent substitution reaction with trifluoromethyltrimethylsilane.

Alternatively, trichloroisocyanuric acid can be used as oxidant in the place of sodium periodate for a newer one-pot synthesis method.

[4] Togni reagent II reacts violently with strong bases and acids, as well as reductants.