Nickel-catalyzed three-component alkene difunctionalization has rapidly emerged as a powerful tool for forging multiple C–C bonds in a single step.

A nickel-catalyzed conjunctive cross-coupling between non-conjugated alkenes, aryl iodides, and alkylzinc reagents is reported. Excellent regiocontrol is achieved utilizing an 8-aminoquinoline directing group that can be readily cleaved to unmask net β,γ-dicarbofunctionalized carboxylic acid products. Under optimized conditions, both terminal and internal alkene substrates provided the corresponding alkyl/aryl difunctionalized products in moderate to excellent yields. The methodology developed herein represents the first three-component 1,2-dicarbofunctionalization of non-conjugated alkenes involving a C(sp)-C(sp) reductive elimination step.

We report that Ni(COD)(DQ) (COD = 1,5-cyclooctadiene, DQ = duroquinone), an air-stable 18-electron complex originally described by Schrauzer in 1962, is a competent precatalyst for a variety of nickel-catalyzed synthetic methods from the literature. Due to its apparent stability, use of Ni(COD)(DQ) as a precatalyst allows reactions to be conveniently performed without use of an inert-atmosphere glovebox, as demonstrated across several case studies. Scheme 1. Overview of the growing nickel precatalyst toolkit.

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A substrate-directed approach to couple alkylzinc nucleophiles, alkyl halide electrophiles, and non-conjugated alkenes under nickel catalysis is described.

Several research groups have recently developed methods to employ configurationally stable, enantioenriched organometallic nucleophiles in stereospecific Pd-catalyzed cross-coupling reactions.

Reductive concerted proton–electron transfer (CPET) is poorly developed for the reduction of C–C π-bonds, including for activated alkenes that can succumb to deleterious pathways (e.g., a competing hydrogen evolution reaction or oligomerization) in a standard electrochemical reduction. We demonstrate herein that selective hydrogenation of the C–C π-bond of fumarate esters can be achieved via electrocatalytic CPET (eCPET) using a CPET mediator comprising cobaltocene with a tethered Brønsted base. High selectivity for electrocatalytic hydrogenation is observed only when the mediator is present. Mechanistic analysis sheds light on two distinct kinetic regimes based on the substrate concentration: low fumarate concentrations operate via rate-limiting CPET followed by an electron-transfer/proton-transfer (ET/PT) step, whereas high concentrations operate via CPET followed by a rate-limiting ET/PT step.

We report a regioselective, nickel-catalyzed syn-1,2-carboamination of non-conjugated alkenyl carbonyl compounds with O-benzoyl hydroxylamine (N-O) electrophiles and aryl/alkylzinc nucleophiles to afford β-and γ-amino acid derivatives. This method enables preparation of products containing structurally diverse tertiary amine motifs, including heterocycles, and can also be used to form quaternary carbon centers. The reaction takes advantage of a tethered 8-aminoquinoline directing group to control the regiochemical outcome and suppress two-component coupling between the N-O electrophile and organozinc nucleophile. File list (4) download file view on ChemRxiv Manuscript.pdf (544.78 KiB) download file view on ChemRxiv Supporting Info.pdf (40.39 MiB) download file view on ChemRxiv 3a.cif (379.57 KiB) download file view on ChemRxiv 4a.cif (835.