Pyridine•BrF3, the missing link for clean fluorinations of aromatic derivatives.

This work demonstrates the unique features of the never used before Py•BrF(3) complex in the field of aromatic organic fluorinations. The main disadvantage of the noncomplexed BrF(3) is the fact that usually, in addition to the desired fluorination, a parallel electrophilic aromatic bromination takes place as well. Use of the Py•BrF(3) complex reduces this electrophilic bromination, which is observed with most reagents based on fluorine and bromine [BrF].

Activation of a CH bond in polypyridine systems by acetyl hypofluorite made from F2.

Activation of the relatively inactive polypyridine backbone with strong electrophilic fluorine, originating from acetyl hypofluorite (AcOF) enables attack of the acetoxy moiety at the α position to the heteroatom. Derivatives of bipyridine, phenanthroline and terpyridine systems have been acetoxylated or oxygenated within a few minutes usually in very good yields.

Synthesis of difluoroaryldioxoles using BrF3.

A novel synthesis of different aromatic and heteroaromatic difluorodioxole derivatives has been developed. The starting materials were catechols, which, after treatment with thiophosgene, formed at 0 °C the respective thiodioxoles. The latter were reacted for a short time with commercially available bromine trifluoride, producing potentially biologically important difluoroaryldioxoles in moderate to high yields.

Toward the synthesis of the rare N-(trifluoromethyl)amides and the N-(difluoromethylene)-N-(trifluoromethyl)amines [RN(CF3)CF2R'] using BrF3.

A synthesis of a wide range of different aliphatic, aromatic, and heterocyclic N-(trifluoromethyl)amides along with aromatic N-(difluoromethylene)-N-(trifluoromethyl)amine derivatives has been developed. The starting materials are the easily available isothiocyanates, and the fluorinating reagent is the commercially available bromine trifluoride. The reaction is performed under mild conditions, and the fluorinated amides and amines are produced in moderate to high yields.

Constructing the OCF2O moiety using BrF3.

A general preparation for aromatic and aliphatic, cyclic as well as linear, symmetric and asymmetric difluoromethylenedioxy derivatives is described. The alcohols were reacted with thiophosgene to give thiocarbonates, which in turn were reacted with BrF3. The fluorination step is complete in seconds with moderate to high yields under mild conditions.