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An efficient method for the C–N cross-coupling of (hetero)aryl (pseudo)halides with optically pure α-amino acid esters employing a commercially available nickel catalyst and weak inorganic base was developed. This is the first example of Ni-catalyzed N-arylation of amino acid esters without the use of electrochemistry, which was shown to effectively couple a variety of amino acid tert-butyl esters with (hetero)aryl chlorides, bromides, and tosylates in high yields and excellent enantioretention. Base-mediated racemization was revealed during control experiments, but increasing the steric bulk of the amino acid ester group limited the amount of racemization of the product.

Co(iii)-catalysed sequential C–H bond addition to dienes and acetic formic anhydride results in a rare example of intermolecular carboformylation, generating versatile α-quaternary aldehyde products that are inaccessible via hydroformylation methods.

All carbon α-quaternary aldehydes are prepared

The first nickel-catalyzed N-arylation of amides with (hetero)aryl (pseudo)halides employing an organic amine base is described. By using a bis(cyclooctadienyl)nickel/8-[2-(dicyclohexylphosphinyl)phenyl]-1,3,5,7-tetramethyl-2,4,6-trioxa-8-phosphaadamantane catalyst mixture in combination with DBU/NaTFA as a dual-base system, a diversity of (hetero)aryl chloride, bromide, tosylate, and mesylate electrophiles were successfully cross-coupled with structurally diverse primary amides, as well as a selection of secondary amide, lac­tam, and oxazolidone nucleophiles.

An efficient and stereoselective Co(III)-catalyzed sequential C─H bond addition to 1,3-enynes and aldehydes is disclosed. This transformation represents the first example of sequential C─H bond additions to 1,3-enynes and a second coupling partner and provides the first example of preparing allenes by C─H bond addition to 1,3-enynes. A wide range of aldehydes, C─H bond substrates and 1,3-enynes with large substituents on the alkynes are effective substrates. The allenyl alcohol products can be further converted to dihydrofurans with high stereoselectivity either in situ or under Ag-mediated cyclization conditions. The allenyl silyl group can also be transferred to the adjacent alcohol by a Brook rearrangement. Moreover, a mechanism for the transformation is proposed supported by X-ray structural characterization of a cobaltacycle intermediate.

4-Amino-1,8-naphthalimides, potentially useful fluorescent probes in biological applications, are prepared via Ni(cod)

The base metal-catalyzed C-N cross-coupling of bulky α,α,α-trisubstituted primary alkylamines with (hetero)aryl electrophiles represents a challenging and under-developed class of transformations that is of significant potential utility, including in the synthesis of lipophilic active pharmaceutical ingredients. Herein, we report that a new, air-stable Ni(II) pre-catalyst incorporating the optimized ancillary ligand PhPAd-DalPhos enables such transformations of (hetero)aryl chloride, bromide, and tosylate electrophiles to be carried out for the first time with substrate scope rivalling that achieved using state-of-the-art Pd catalysts, including room temperature cross-couplings of (hetero)aryl chlorides that are unprecedented for any catalyst (Pd, Ni, or other).

We report herein on the results of our combined experimental/computational study regarding the catalytic performance of PAd-DalPhos (L1) in nickel-catalyzed ammonia arylation for primary aniline synthesis. Primary arylamine C–N reductive eliminations occurring from arylnickel(II) parent amido complexes of the type (L)Ni(Ph)(NH2) were modeled by use of density-functional theory (DFT) methods, for a series of L1 derivatives. The dual aims were to assess the effect of structural modifications to L1 on potentially rate-limiting C–N reductive elimination and to identify promising candidates for experimental inquiry. Increasing the steric demand of the Paryl groups from o-tolyl (in L1) to mesityl (in L16) resulted in a significant lowering of the barrier to C–N reductive elimination (ΔG⧧RE), which can be attributed in part to interactions between the ligand Paryl groups and the nickel-bound amido ligand, as observed in noncovalent interaction (NCI) plots of the reductive elimination transition-state structures....

Whereas the metal-catalyzed C(sp2)–N cross-coupling of cyclopropylamine with aryl electrophiles represents an attractive route to pharmaceutically relevant N-arylcyclopropylamines, few catalysts that are capable of effecting such transformations have been identified. Herein, the nickel-catalyzed C(sp2)–N cross-coupling of cyclopropylamine and related nucleophiles, including ammonium salts, with (hetero)aryl (pseudo)halides is reported for the first time, with the demonstrated scope of reactivity exceeding that displayed by all previously reported catalysts (Pd, Cu, or other). Our preliminary efforts to effect the N-arylation of cyclopropylamine with (hetero)aryl chlorides at room temperature by use of (L)NiCl(o-tolyl) precatalysts (L = PAd-DalPhos, C1; L = JosiPhos CyPF-Cy, C2) were unsuccessful, despite the established efficacy of C1 and C2 in transformations of other primary alkylamines. However, systematic modification of the ancillary ligand (L) structure enabled success in such transformations, with ...

The use of (L)Ni(o-tolyl)Cl precatalysts (L = PAd-DalPhos or CyPAd-DalPhos) enables the C(sp2)–O cross-coupling of primary, secondary, or tertiary aliphatic alcohols with (hetero)aryl electrophiles, including unprecedented examples of such nickel-catalyzed transformations employing (hetero)aryl chlorides, sulfonates, and pivalates. In addition to offering a competitive alternative to palladium catalysis, this work establishes the feasibility of utilizing ancillary ligation as a complementary means of promoting challenging nickel-catalyzed C(sp2)–O cross-couplings, without recourse to precious-metal photoredox catalytic methods.