Regioselective CF Bond Activation of Hexafluoropropylene on Palladium(0): Formation of a Cationic η²‐Perfluoroallylpalladium Complex

Abstract

A chemoselective C(sp(2) )F or C(sp(3) )F bond activation of hexafluoropropylene (HFP) was achieved by adopting the proper combination of a Lewis acid co-additive with a ligand which coordinates Pd(0) . The treatment of [(η(2) -HFP)Pd(PCy3 )2 ] with B(C6 F5 )3 allowed a chemoselective C(sp(3) )F bond cleavage of HFP to give a unique cationic perfluoroallypalladium complex. In this complex, the coordination mode of the perfluoroallyl ligand was considered to be of the unique η(2) -fashion.

Reactions of Fluoroalkenes with an Aluminium(I) Complex

“…In both cases the C = Cb ond of hexafluoropropene is retained in the organoaluminium compound, with comparable bond lengths of 1.310(6) and 1.325(4) in 4a and 4b,r espectively.T he precise origin of this selectivity remains somewhat unclear, although the reactivity of hexafluoropropene with 1 is consistent with many examples of addition of nucleophiles to this substrate. [14,[32][33][34][35][36] Expanding the investigation to fluoroalkenes that do not contain sp 2 C À Fb onds leads to equally facile sp 3 C À Fb ond activation. Ther eaction of 1 with 3,3,3-trifluoropropene yields 5 (Scheme 3).…”

Catalytic Enantioselective and Diastereoselective Allylic Alkylation with Fluoroenolates: Efficient Access to C3‐Fluorinated and All‐Carbon Quaternary Oxindoles

“…[22] To this end, progress with aliphatic substrates has been largely limited by the chemical inertness and stability of the C sp3 -F bond. Intriguing reports on fluoride/halide exchange [23] and aliphatic C-F bond cleavage followed by carbon-heteroatom [24] or carbon-carbon coupling [25] have emerged in the last few years.…”

Improving selectivity in catalytic hydrodefluorination by limiting SNV reactivity

“…Fig. 7-9 show some illustrative cut outs of a 19 F NMR spectra of a reaction mixture containing 1 st and 2 nd HDF products. Allylic HDF products show characteristic chemical shifts and coupling constants for the CF 2…”

“…82 Data for HDF of 4. 4a: 1 H (400 MHz, C 6 D 6 ): δ = 7.12 (1H, tdd, 2 J HF = 51.3 Hz, 3 J HF = 15.6 Hz, 4 J HF = 2.5 Hz, -CF 2 H) ppm; 19 F external optimizer (PQS; convergence settings: DMAX 0.1, TOLG 0.0003, TOLE 0.00004, TOLD 0.0018) 84,85 instead of the internal Gaussian optimizer, using an ultrafine grid (Int(Grid = ultrafine)) and standard SCF convergence quality settings (Scf = tight) for Gaussian single point calculations. The nature of each stationary point was checked with an analytical second-derivative calculation (no imaginary frequency for minima, exactly one imaginary frequency for transition states, corresponding to the reaction coordinate) and the accuracy of the TS was confirmed with an IRC scan.…”