C(sp²)-CF₃ Reductive Elimination from Well-Defined Argentate(III) Complexes [nBu₄N][Ag(Ar)(CF₃)₃]

Abstract

The preparation of a series of well-defined, shelf-stable square planar aryl­(tris­(trifluoromethyl))­argentate­(III) complexes [nBu4N]+[Ag­(Ar)­(CF3)3]− and their C­(sp2)-CF3 bond-forming reductive elimination are described. Mechanistic studies of the C­(sp2)-CF3 reductive elimination from these complexes, including kinetic studies, effect of temperature and solvent, and DFT calculations, indicate that the C­(sp2)-CF3 bond-forming process occurred via a concerted reductive elimination pathway.

Origin of the different reactivity of the high‐valent coinage‐metal complexes [RCuiiiMe3]− and [RAgiiiMe3]− (R=allyl)**

“…The fact that double-shell orbitals are significantly entangled -and therefore relevant for the active space -only for the late 3d-metals and not for the homologous 4d-metals has been documented before. [56,59,60] Following the common CAS(N,L) notation with the number of active electrons N, and the number of active orbitals L, we denote these active spaces CAS (10,11) in case of copper, and CAS (10,10) in case of silver (plots of the final set of orbitals for the equilibrium structures and the multi-configurational cis-cyclic, trans-cyclic and outersphere cross-coupling TSs of the [RMMe 3 ] À complexes are shown in Figures S8-S15). This selection ensures a consistent active space for all [RMMe 3 ] À species and corresponding dissociation products discussed here and therefore guarantees size-consistency.…”

“…Multi-configurational Z s(1) diagnostic for the equilibrium and CÀ C coupling transition state (TS) structures of [RMMe 3 ] À as well as for the [MMe 3 ] *À fragment complex (M = Cu, Ag; R = η 1 -allyl). The diagnostic was evaluated from the CAS (10,11) active space for M = Cu and the CAS(10,10) active space in case of M = Ag. function that is likely to be poorly described by singleconfigurational approaches.…”

“…[1,2] In contrast, analogous silver-mediated transformations are by far not that well established, [3,4] but the potential of silver to mediate the formation of carbon-carbon bonds has become a greater focus of attention just recently. [5][6][7][8][9][10] While the usefulness of organo-LiAgMe 2 •LiI/RI reaction system (Figure 1). [7] In the reaction solution of the organocuprate, the analogous ate complex [RCuMe 3 ] À was detected as well, but the results of the RI-NMR spectroscopic experiments indicated that the latter reacted towards the neutral [RCuMe 2 ] species and did not undergo a CÀ C coupling reaction (Figure 1, top).…”

“…Copper‐mediated C−C coupling reactions play an outstanding role in the field of organic synthesis [1,2] . In contrast, analogous silver‐mediated transformations are by far not that well established, [3,4] but the potential of silver to mediate the formation of carbon‐carbon bonds has become a greater focus of attention just recently [5–10] . While the usefulness of organoargentates in stoichiometric alkylation reactions was questioned on the basis of theoretical calculations and gas‐phase experiments in the past, [11,12] a collaboration between a few of us and the Ogle group has recently shown that a LiAgMe 2 ⋅LiI reagent indeed undergoes a cross‐coupling reaction with allyl iodide in THF [7] .…”

Cover Feature: Cross‐Coupling through Ag(I)/Ag(III) Redox Manifold (Chem. Eur. J. 62/2021)

“…[8] Pioneering work by Ritter, Li, Hartwig and Sarpong allowed for the fluorination of distinct skeletons and pointed to the capital role of elusive Ag II F or Ag III F compounds. [9,10] Most astonishing, organosilver(III) species effecting cross-coupling were authenticated by Ribas, [11] Menjón [12] and Shen [13] who accomplished C−C and C−heteroatom bond formations nurtured by aryl−Ag III catalyst I, [11] or the trifluoromethylation of thiols and arenes enabled by the anions [Ag III (F)(CF3)3] -II [12] and [Ag III (aryl)(CF3)3] -III, [13] respectively (Fig. 1A).…”