Fluorinating reagents and fluoroalkylation
The introduction of fluorine atoms or fluoroalkyl groups into
leads to greater effectiveness in many cases. This step frequently occurs in a late stage of synthesis. This process is reflected in the term “late-stage-fluorination”.
Gaseous fluorine, hydrogen fluoride,4) and derivates such as
or quaternary ammonium fluorides are available to the chemist as reagents for fluorination, amongst others. Recent developments represent
(Fluolead®) as well as
halogen fluorides (e.g. iodine pentafluoride),
Metal fluorides such as aluminium, antimony, silver, molybdenum or5) or
(ReF6) in the abcr catalogue.
are used, depending on the substrate. You can also find gaseous fluorides such as
You can also choose between the following for the fluoroalkylation of diverse reagents:
3 sources, having been continuously refined over the years.
(FIM) represents an easy to handle reagent for the introduction of fluoromethyl groups.
or difluoromethyl groups can typically be transferred via so-called
These hypervalent iodine compounds act as electrophilic CF
Besides electrophilic CH2F, CHF2 and CF3 sources, nucleophilic, radical or carbenoid sources are also used. Many of these reagents are based on sulfonium or sulfonyl compounds, thus for instance the
Other examples of trifluoromethylation reagents are represented by3),
(CF3SO2Na). On account of its instability, trifluoromethyllithium (CF3Li) is not available to synthesis chemists. Complexed trifluorumethyl copper reagents provide alternatives here.
You can also find a series of trifluorumethoxy- or trifluoromethylthio-substituted
in the abcr catalogue.
are long known, the corresponding pentafluoroethyl compounds have only become accessible recently. For the introduction of pentafluoroethyl groups, abcr recommends the new reagent
This is available as a solid with long-term stability and does not require any gaseous educts.