Ni-Catalyzed Regioselective β,δ-Diarylation of Unactivated Olefins in Ketimines via Ligand-Enabled Contraction of Transient Nickellacycles: Rapid Access to Remotely Diarylated Ketones (original) (raw)
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Journal of the American Chemical Society, 2018
We disclose unprecedented synergistic bimetallic Ni/Ag and Ni/Cu catalysts for regioselective ,-diarylation of unactivated alkenes in simple ketimines with aryl halides and arylzinc reagents. The bimetallic synergy, which generates cationic Ni(II) species during reaction, promotes migratory insertion and transmetalation steps, and suppresses -H elimination and crosscoupling, the major side reactions that cause serious problems during alkene difunctionalization. This diarylation reaction proceeds at remote locations to imines to afford, after simple H + workup, diversely substituted ,-diarylketones that are otherwise difficult to access readily with existing methods.
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The arylation of heteroatom nucleophiles is a central strategy to reach diarylated compounds that are key building blocks in agrochemicals, materials and pharmaceuticals. Nucleophilic aromatic substitution is a classical tool for such arylations, and hypervalent iodine-mediated arylations are modern alternatives to achieve a wider scope of products. Herein, we combine the benefits of those strategies to enable an atom-efficient and transition metal-free functionalization of N- and O- nucleophiles with two structurally different aryl groups, to provide di- and triarylamines and diaryl ethers in one single step (> 100 examples). The core of this strategy is the unique reactivity discovered with certain fluorinated diaryliodonium salts, which unveils novel reaction pathways in hypervalent iodine chemistry. The method is suitable for aliphatic amines, anilines, ammonia and even water and tolerates a wide variety of functional and protecting groups. Furthermore, the retained iodine su...
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All the reactions were set up inside a nitrogen-filled glovebox and all the chemicals were handled under nitrogen atmosphere unless stated otherwise. All the glassware including the 4-dram, 1-dram borosilicate (Kimble-Chase) vials, and pressure vessels were properly dried in an oven before use. Bulk solvents were obtained from EMD, anhydrous solvents (DMF, DMA, DMSO, NMP, dioxane, toluene, MeCN) were obtained from Sigma-Aldrich and were used directly without further purification. Deuterated solvents were purchased from Sigma-Aldrich. NiCl2 was purchased from Alfa-Aesar. 1 H, 13 C and 19 F NMR spectra were recorded on a Bruker instrument (300, 75 and 282 MHz respectively) and internally referenced to the residual solvent signals of CDCl3 for 1 H and 13 C NMR, and C6F6 for 19 F NMR at 7.26 ppm, 77.16 ppm and −164.9 ppm respectively. The chemical shifts of NMR and the coupling constants (J) for 1 H, 13 C and 19 F NMR are reported in δ parts per millions (ppm) and in Hertz, respectively. The following conventions are used for multiplicities: s, singlet; d, doublet; t, triplet; q, quartet; m, multiplet; dd, doublet of doublet; s, br, singlet broad; ddd, doublet of doublet of doublet. High resolution mass spectra of new compounds were recorded at the mass spectrometry facility, Department of Chemistry and Chemical Biology, University of New Mexico (UNM). All NMR spectra were collected at Department of Chemistry and Chemical Biology, UNM. The X-ray data were measured on a Bruker Kappa APEXII Duo system equipped with a fine-focus sealed tube (Mo Kα, λ = 0.71073 Å) and a graphite monochromator at the X-ray facility at the University of Virginia. Infrared (IR) spectra were recorded on Bruker Alpha-P ATR-IR at UNM and νmax is reported in cm-1 at UNM. 2. Experimental Section 2.1. Preparation of Substrates ethyl 2-cyanopent-4-enoate was prepared following literature procedure. 1
Chemical Science, 2020
The selective 1,2-aminoacylation of olefins provides opportunities for the rapid construction of nitrogencontaining molecules. However, the lack of CO-free acylation reactions has limited their application. By using photoredox proton-coupled electron transfer (PCET)/Ni dual-catalysis, a highly regio-and diastereoselective amidoacylation of unactivated olefins has been developed. Various acyl electrophiles are compatible, including alkyl-and aryl acyl chlorides and anhydrides, as well as in situ activated carboxylic acids. Hammett studies and other mechanistic experiments to elucidate features of the diastereoselectivity, a transient absorption study of the PCET step, as well as computational evidence, provide an in-depth understanding of the disclosed transformation.
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Proceedings of the National Academy of Sciences, 2010
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