Tuning NaCo(II) Bimetallic Cooperativity to Perform Co-H Exchange / C-F Bond Activation Processes in Polyfluoroarenes.

Recent advances in cooperative chemistry have shown the potential of heterobimetallic complexes combining an alkali-metal with an earth abundant divalent transition metal for the functionalisation of synthetically relevant aromatic molecules via deprotonative metalation. Pairing sodium with cobalt (II), here we provide an overview of the reactivity of bimetallic [NaCo(HMDS)3] [HMDS = N(SiMe3)2] towards C-H and C-F functionalisation of a wide range of perfluorinated molecules. These studies also uncover the enormous potential of this heterobimetallic base to perform Co-H exchanges with excellent selectivity and exceptional stoichiometric control as well as shedding light on the key role played by the alkali-metal.

Unlocking the Metalation Applications of TMP-powered Fe and Co(II) bis(amides): Synthesis, Structure and Mechanistic Insights.

Typified by LiTMP and TMPMgCl.LiCl, (TMP=2,2,6,6-tetramethylpiperidide), s-block metal amides have found widespread applications in arene deprotonative metalation. On the contrary, transition metal amides lack sufficient basicity to activate these substrates.

Main group metal-mediated strategies for C-H and C-F bond activation and functionalisation of fluoroarenes.

With fluoroaromatic compounds increasingly employed as scaffolds in agrochemicals and active pharmaceutical ingredients, the development of methods which facilitate regioselective functionalisation of their C-H and C-F bonds is a frontier of modern synthesis. Along with classical lithiation and nucleophilic aromatic substitution protocols, the vast majority of research efforts have focused on transition metal-mediated transformations enabled by the redox versatilities of these systems. Breaking new ground in this area, recent advances in main group metal chemistry have delineated unique ways in which s-block, Al, Ga and Zn metal complexes can activate this important type of fluorinated molecule.

Applying Na/Co(II) bimetallic partnerships to promote multiple Co-H exchanges in polyfluoroarenes.

Heterobimetallic base NaCo(HMDS) [HMDS = N(SiMe)] enables regioselective di-cobaltation of activated polyfluoroarenes under mild reaction conditions. For 1,3,5-CHX (X= Cl, F), NaCo(HMDS) in excess at 80 °C impressively induces the collective cleavage of five bonds (two C-H and three C-X) of the substrates a cascade activation process that cannot be replicated by LiCo(HMDS) or KCo(HMDS).

Building Square Planar Cobalt (II) Complexes via Sodium Mediated Cobaltation of Fluoroarenes.

While cobalt complexes have already shown their potential for C-H and C-F bond activation of fluoroarenes, their reactivity as metalating agents via Co-H exchange towards these substrates has not been explored. Herein, we report a Co(HMDS) [HMDS=N(SiMe ) ] system which, when synergistically enhanced via sodium amide Na(HMDS) mediation, can render chemo- and regioselective cobaltation of a series of fluoroarenes to produce a new class of homoleptic square planar [Na CoAr ] complexes. Density functional theory calculations elucidate the key roles of the Na/Co counterparts in a stepwise sodiation/cobalt transmetalation process, leading to this novel C-H metalation.

Alkali Metal Metal(ates) Containing Divalent Earth Abundant Transition Metals.

Recent advances in cooperative chemistry have shown the enormous potential of main group heterobimetallic complexes for the functionalisation of aromatic molecules. Going beyond main group metal chemistry, here we provide an overview on the synthesis, structure and reactivity of bimetallic complexes which combine an alkali-metal (AM= Li, Na) with a divalent earth-abundant transition metal (M= Mn, Fe, Co, Ni), containing the utility silyl amide HMDS (HMDS = N(SiMe3)2). Advancing the understanding on how cooperative effects operate in these bimetallic (ate) systems, selected examples of their applications in deprotonative metalation are also discussed with special emphasis on the constitution of the metalated intermediates.