Triflic anhydride is the chemical compound

Chemical compound

A chemical compound is a pure chemical substance consisting of two or more different chemical elements that can be separated into simpler substances by chemical reactions. Chemical compounds have a unique and defined chemical structure; they consist of a fixed ratio of atoms that are held together...

 with the formula (CF₃SO₂)₂O. This compound is a particularly strong electrophile

Electrophile

In general electrophiles are positively charged species that are attracted to an electron rich centre. In chemistry, an electrophile is a reagent attracted to electrons that participates in a chemical reaction by accepting an electron pair in order to bond to a nucleophile...

, useful for introducing the triflyl group

Trifluoromethylsulfonyl

Triflyl, more formally known as trifluoromethanesulfonyl, is a functional group with the formula F3CSO2–. The triflyl group is often represented by –Tf....

, CF₃SO₂. Triflic anhydride is the acid anhydride of the strong acid triflic acid, CF₃SO₂OH.

It can be assayed by ¹⁹F NMR spectroscopy: −72.6 ppm vs. -77.3 for TfOH (std CFCl₃).

Preparation

The compound is prepared by dehydration of triflic acid using phosphorus pentoxide

Phosphorus pentoxide

Phosphorus pentoxide is a chemical compound with molecular formula P4O10 . This white crystalline solid is the anhydride of phosphoric acid. It is a powerful desiccant.-Structure:...

:

2CF₃SO₂OH + P₄O₁₀ → [CF₃SO₂]₂O + P₄O₉(OH)₂

Illustrative uses

In a representative application, is used to convert an imine into a NTf group.

It will convert phenol

Phenol

Phenol, also known as carbolic acid, phenic acid, is an organic compound with the chemical formula C6H5OH. It is a white crystalline solid. The molecule consists of a phenyl , bonded to a hydroxyl group. It is produced on a large scale as a precursor to many materials and useful compounds...

s into a triflic ester, which enables cleavage of the C-O bond.