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Polyfluorinated substituents often enhance effectiveness, improve the stability within metabolic processes, and boost the lipophilicity of biologically active compounds. However, methods for their introduction into aliphatic carbon chains remain very limited. A potentially general route to integrate the fluorinated scaffolds into organic molecules involves insertion of fluorine‐containing carbenes into C(sp3)−H bonds. The electron‐withdrawing characteristics of perfluoroalkyl groups enhances the reactivity of these carbenes which should enable the functionalization of unactivated C(sp3)−H bonds. Curiously, it appears that use of perfluoroalkyl‐containing carbenes in alkane C−H functionalization is exceedingly rare. This concept describes photolysis, enzymatic catalysis, and transition metal catalysis as three primary approaches to C(sp3)−H functionalization by trifluoromethylcarbene and its homologues. [ABSTRACT FROM AUTHOR]

We report here "sandwich"‐diimine copper complex‐catalyzed trifluoroethylation and pentafluoropropylation of unactivated C(sp3)−H bonds in alkyl esters, halides, and protected amines by employing CF3CHN2 and CF3CF2CHN2 reagents. Reactions proceed in dichloromethane solvent at room temperature. Identical C−H functionalization conditions and stoichiometries are employed for generality and convenience. Selectivities for C−H insertions are higher for compounds possessing stronger electron‐withdrawing substituents. Preliminary mechanistic studies point to a mechanism involving a pre‐equilibrium forming a "sandwich"‐diimine copper‐CF3CHN2 complex followed by rate‐determining loss of nitrogen affording the reactive copper carbene. It reacts with trifluoromethyldiazomethane about 6.5 times faster than with 1‐fluoroadamantane explaining the need for slow addition of the diazo compound. [ABSTRACT FROM AUTHOR]

We report structural characterization of a new member of m-phenylene ethynylene ring family. This shape-persistent macrocycle also co-crystallizes with hexafluoro-, 1,2,4,5-tetrafluoro-, 1,3,5-trifluoro, and 1,4-difluorobenzene. The four complexes are almost isostructural, and all show the fluoroarene included into the central cavity of the macrocycle. Characterized by multiple short CH⋅⋅⋅FC contacts, these inclusion complexes further dimerize in the solid state into a 2+2 assembly, in which the two macrocycles embrace each other by their large hydrophobic groups that are rotated by 60° relative to one another. [ABSTRACT FROM AUTHOR]