Cyclic-Protected Hexafluoroacetone as an Air-Stable Liquid Reagent for Trifluoromethylations

Synthesis and application of well-defined [Ph4P]+[Cu(CF2CF3)2]- complex as a versatile pentafluoroethylating reagent

We herein describe the preparation and application of a new bispentafluoroethylated organocuprate [Ph4P]+[Cu(CF2CF3)2]-. This complex has demonstrated a remarkable range of reactivities towards carboxylic acids, diazonium salts, organic halides, boronic esters, terminal alkynes and (hetero)arenes as a versatile pentafluoroethylating reagent. The construction of C(sp3)-/C(sp2)-/C(sp)-CF2CF3 bonds can therefore be achieved using a single reagent.

Catalytic trifluoromethylation of iodoarenes by use of 2-trifluoromethylated benzimidazoline as trifluoromethylating reagent

The trifluoromethylation of iodoarenes was accomplished by use of a 2-trifluoromethylbenzimidazoline derivative as the trifluoromethylating reagent and a catalytic amount of Cu(I) in the presence of 2,2'-bipyridyl as the ligand. Through a mechanistic study, we found that the oxidative addition of the iodoarene to the Cu(I)–CF₃ species is the rate-determining step.

Radical Pentafluoroethylation of Unactivated Alkenes Using CuCF2CF3

We have found that the CuCF₂CF₃ complex generated from low-cost pentafluoroethane is a convenient and practical source for the CF₂CF₃ radical under aerobic conditions at room temperature. Using this system, readily available unactivated alkenes can be pentafluoroethylated to provide novel allylic CF₂CF₃ compounds with excellent E-selectivity and functional group tolerability. Mechanistic studies including TEMPO-CF₂CF₃ trapping and radical clock experiments provided strong evidence for radical pathways, offering a new opportunity for copper-mediated radical perfluoroalkylation.

Copper-based fluorinated reagents for the synthesis of CF2R-containing molecules (R ≠ F)

Over the years, the development of new methodologies for the introduction of various fluorinated motifs has gained a significant interest due to the importance of fluorine-containing molecules in the pharmaceutical and agrochemical industries. In a world eager to eco-friendlier tools, the need for innovative methods has been growing. To address these two challenges, copper-based reagents were developed to introduce CF2H, CF2RF, CF2CH3, CF2PO(OEt)2 and CF2SO2Ph motifs on a broad range of substrates. Copper-based fluorinated reagents have the advantage of being inexpensive and generally in situ generated or prepared in a few steps, which make them convenient to use. In this review, an overview of the recent advances made for the synthesis of fluorinated molecules using copper-based fluorinated reagents will be given.

From C1 to C2 : TMSCF3 as a Precursor for Pentafluoroethylation

A highly efficient copper-mediated aromatic pentafluoroethylation method using TMSCF₃ as the sole fluoroalkyl source is described. The reaction proceeds by a key C₁ to C₂ process, that is, the generation of CuCF₃ from TMSCF₃ , followed by a subsequent spontaneous transformation into CuC₂ F₅ . Various aryl iodides were pentafluoroethylated with the TMSCF₃ -derived CuC₂ F₅ . This method represents the first practical and efficient method for pentafluoroethylation of aryl iodides using commercially available TMSCF₃ as a pentafluoroethyl precursor.