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Herein, we describe nickel oxidative addition complexes (Ni-OACs) of drug-like molecules as a platform to rapidly generate lead candidates with enhanced C( sp 3 ) fraction. The potential of Ni-OACs to access new chemical space has been assessed not only in C( sp 2 )-C( sp 3 ) couplings but also in additional bond formations without recourse to specialized ligands and with improved generality when compared to Ni-catalyzed reactions. The development of an automated diversification process further illustrates the robustness of Ni-OACs, thus offering a new gateway to expedite the design-make-test-analyze (DMTA) cycle in drug discovery.

Notwithstanding recent developments in nickel-catalyzed C-O cross-coupling chemistry, such transformations of substituted phenols and (hetero)aryl chlorides with a useful reaction scope have yet to be reported. In this work, we disclose the results of catalyst screening that allowed the identification of PhPAd-DalPhos/NiCOD 2 as an effective catalyst system under thermal conditions for the O-arylation of substituted phenols with chloropyridine-type electrophiles, leading to pyridyl- O -aryl frameworks that are found in active pharmaceutical ingredients.

Herein we disclose the synthesis of sterically encumbered dialkylnickel(II) complexes bearing 2,9-dimethyl-1,10-phenanthroline ligands. A comparison with their unsubstituted analogues by both X-ray crystallography and theoretical calculations revealed significant distortions in their molecular structures. Eyring plots along with stoichiometric and photoexcitation studies revealed that sterically encumbered dialkylnickel(II) complexes enable facile C( sp 3 )-C( sp 3 ) reductive elimination, thus offering an improved understanding of Ni catalysis., Competing Interests: The authors declare no competing financial interest., (© 2022 The Authors. Published by American Chemical Society.)

We report on our successful development of the first metal-catalyzed mono-α-arylation of carbonyl compounds employing a soluble organic base. The scope of these Ni/DalPhos-catalyzed transformations encompasses a range of (hetero)aryl halides (Cl, Br, I) and phenol-derived electrophiles (sulfonates, carbonates, carbamates, sulfamates), including active pharmaceutical ingredients (chloroquine, clozapine), in combination with the typically problematic feedstock small molecule substrates acetone, dimethylacetamide, and for the first time with any metal catalyst/base, ethyl acetate., (© 2022 Wiley-VCH GmbH.)

The C-N cross-coupling of (hetero)aryl (pseudo)halides with NH substrates employing nickel catalysts and organic amine bases represents an emergent strategy for the sustainable synthesis of (hetero)anilines. However, unlike protocols that rely on photoredox/electrochemical/reductant methods within Ni I/III cycles, the reaction steps that comprise a putative Ni 0/II C-N cross-coupling cycle for a thermally promoted catalyst system using organic amine base have not been elucidated. Here we disclose an efficient new nickel-catalyzed protocol for the C-N cross-coupling of amides and 2'-(pseudo)halide-substituted acetophenones, for the first time where the (pseudo)halide is chloride or sulfonate, which makes use of the commercial bisphosphine ligand PAd2-DalPhos (L4) in combination with an organic amine base/halide scavenger, leading to 4-quinolones. Room-temperature stoichiometric experiments involving isolated Ni 0, I, and II species support a Ni 0/II pathway, where the combined action of DBU/NaTFA allows for room-temperature amide cross-couplings., (© 2022 Wiley-VCH GmbH.)

The Ni-catalyzed N-arylation of β-fluoroalkylamines with broad scope is reported for the first time. Use of the air-stable pre-catalyst (PAd2-DalPhos)Ni(o-tol)Cl allows for reactions to be conducted at room temperature (25 °C, NaOtBu), or by use of a commercially available dual-base system (100 °C, DBU/NaOTf), to circumvent decomposition of the N-(β-fluoroalkyl)aniline product. The mild protocols disclosed herein feature broad (hetero)aryl (pseudo)halide scope (X=Cl, Br, I, and for the first time phenol-derived electrophiles), encompassing base-sensitive substrates and enantioretentive transformations, in a manner that is unmatched by any previously reported catalyst system., (© 2020 Wiley-VCH GmbH.)

The development of Ni-catalyzed C-N cross-couplings of sulfonamides with (hetero)aryl chlorides is reported. These transformations, which were previously achievable only with Pd catalysis, are enabled by use of air-stable (L)NiCl(o-tol) pre-catalysts (L=PhPAd-DalPhos and PAd2-DalPhos), without photocatalysis. The collective scope of (pseudo)halide electrophiles (X=Cl, Br, I, OTs, and OC(O)NEt 2 ) demonstrated herein is unprecedented for any reported catalyst system for sulfonamide C-N cross-coupling (Pd, Cu, Ni, or other). Preliminary competition experiments and relevant coordination chemistry studies are also presented., (© 2020 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)