From Academia to the Market – Air-stable Ni(II)/Josiphos Catalysts

The design, synthesis, commercialization and application of air stable Ni(II)/Josiphos complexes has been realized in a collaboration between Solvias and ICBMS (University Lyon 1). The Ni-complexes  are utilized as versatile precatalysts for diverse cross coupling reactions. Apart from being active in established C–C and C–N couplings at low catalyst loadings, the novel Ni-precatalysts enabled the development of the challenging monoarylation of ammonia, ammonia surrogates and even alkylammonium chlorides with aryl carbamates. Finally, the alpha-arylation of acetone with aryl chlorides, carbamates and pivalates was demonstrated using the Ni(II)/Josiphos precatalysts

Nouvelle approche duale métallique-organique pour la catalyse de polymérisation d'esters cycliques (du concept de coopérativité vers la synthèse de polyesters à architectures originales)

TOULOUSE3-BU Sciences (315552104) / SudocSudocFranceF

A unified photocatalytic strategy for the cross coupling of alcohols with aryl halides enabled by synergistic nickel and iron LMCT catalysis

The use of alcohol feedstock as coupling partner in cross coupling reactions offers an extraordinary potential for the effi-cient synthesis of Csp3-rich complex molecular scaffolds. This prominent strategy relies on the generation of alkoxy radicals, which can react via various radical pathways to give carbon-centered radicals that can be engaged in C-C bond formation reactions. However, cross-coupling reactions involving catalytic generation of alkoxy radicals directly from native alcohols is highly challenging and the scope of existing catalytic methods remains particularly limited. Moreover, a unified strategy that can incorporate a broad range of alcohols in catalytic cross-coupling with aryl halides is currently unavailable. Herein, we report a general photocatalytic platform that combines nickel and iron ligand-to-metal charge transfer (LMCT) catalysis for the selective deconstructive Csp2-Csp3 bond cleavage and arylation of various unactivated alcohols. This protocol lever-ages the ability of photoinduced iron LMCT catalysis to generate radicals from diversely substituted alcohols, enabling im-plementation of various C-C bond-forming manifolds. These include dehydroxymethylative arylation of aliphatic alcohols, remote arylation of cyclic alcohols to yield alkyl ketones, and unprecedented use of tertiary alcohols for methylation of aryl halides. This methodology offers a practical and unified strategy for engaging a large variety of commercially available alcohols in cross-coupling reactions under mild conditions, using abundant nickel and iron catalysts. Mechanistic studies, including stoichiometric organometallic chemistry and cyclic voltammetry, provide unprecedented insights into the crucial role of the ancillary ligand surrounding the iron catalyst in stabilizing high-valent photo-catalytically active intermediates

Synthesis, structure and reactivity of an NHC silyl gold(I) complex

International audienceThe first example of a silyl gold(I) complex stabilized by an N-heterocyclic carbene (NHC) was synthesised and fully characterized, including crystallographically. The syn insertion of methyl propiolate into the Au-Si bond leading to a vinyl gold complex is reported. As substantiated by X-ray diffraction analysis, the reaction proceeds with opposite regioselectivity compared to that observed previously with phosphine silyl gold(I) complexes

Ring-Opening Polymerization with Zn(C6F5)2-Based Lewis Pairs: Original and Efficient Approach to Cyclic Polyesters

International audienceDual systems combining Zn(C6F5)2 with an organic base (an amine or a phosphine) promote the controlled ring-opening polymerization of lactide and ε-caprolactone. The Lewis pairs cooperate to activate the monomers, affording well-defined high molecular weight cyclic polyesters. Efficient chain-extension gives access to cyclic block copolymers

Silyl Radical Mediated Cross-Electrophile Coupling of N -Acyl-imides with Alkyl Bromides under Photoredox/Nickel Dual Catalysis

International audienceA photoredox Ni-catalyzed cross-coupling of N-acyl-imides with unactivated alkyl bromides has been developed that enables efficient access to a variety of functionalized alkyl ketones, including unsymmetrical dialkyl ketones, under very mild and operationally practical conditions. The reaction that operates without the need for any preformed carbon nucleophile proceeds via the combination of two different bond activation processes, i.e. Ni-catalyzed imide activation via C(acyl)–N bond cleavage and (TMS)3Si radical-mediated alkyl halide activation via halogen-atom abstraction

Gold(I)/Gold(III) Catalysis that Merges Oxidative Addition and π‐Alkene Activation

International audienceThe hetero-arylation of alkenes with aryl iodides has been efficiently achieved with the (MeDalphos)AuCl complex via Au(I)/Au(III) catalysis. The possibility to combine oxidative addition of aryl iodides and π-activation of alkenes at gold is demonstrated for the first time. The reaction is robust and general (>30 examples including internal alkenes, 5, 6 and 7-membered rings). It is regioselective and leads exclusively to trans addition products. The (P,N) gold complex is most efficient with electron-rich aryl substrates, which are troublesome with alternative photoredox / oxidative approaches. In addition, it actuates a very unusual switch in regioselectivity from 5-exo to 6-endo cyclization between the Z and E isomers of internal alkenols

C(sp3)–H Bond Acylation with N-Acyl Imides under Photoredox/ Nickel Dual Catalysis

International audienceA novel Ni/photoredox-catalyzed acylation of aliphatic substrates, including simple alkanes and dialkyl ethers, has been developed. The method combines C–N bond activation of amides with a radical relay mechanism involving hydrogen-atom transfer. The protocol is operationally simple, employs bench-stable N-acyl imides as acyl-transfer reagents, and permits facile access to alkyl ketones under very mild conditions