Visible-Light Enabled C(sp³)–C(sp²) Cross-Electrophile Coupling via Synergistic Halogen-Atom Transfer (XAT) and Nickel Catalysis

Abstract

We herein report the first visible-light-mediated cross-coupling of unactivated alkyl iodides with aryl bromides through synergistic halogen atom transfer (XAT) and nickel catalysis. This simple protocol operates under mild reaction conditions and tolerates a variety of functional groups affording C­(sp 3)–C­(sp 2) cross-coupling products in good to moderate yields.

α‐Amino Radical Halogen Atom Transfer Agents for Metallaphotoredox‐Catalyzed Cross‐Electrophile Couplings of Distinct Organic Halides

“…A particularly attractive feature of the method is it can deliver products in high yields when employing either coupling partner as the limiting reactant, allowing user‐flexibility to accommodate and limit the organic halide partner with greatest cost or pharmaceutical importance. As demonstrated herein by the broad scope of applications in late‐stage functionalization, this method represents an attractive tool for synthetic and medicinal chemists to rapidly build molecular complexity and contributes to a rapidly developing field of XAT dual first‐row transition metal catalysis [11,12,22,23] . Future challenges include expanding the scope of organic halide partners to aryl/alkyl chlorides without bulky silane XAT agents.…”

Efficient amine oxidation using metal–organic framework photocatalysts for aminoalkyl radical-mediated halogen-atom transfer

“…68,69 The scope of halides reacting with peruorobenzene was also studied. Cyclic and heterocycloalkyl halides (24)(25) provided the desirable products in good yields (43-54%), whereas, halides with alkyl groups (26) showed a lower yield of 30%, which should be due to the formation of less-stable primary alkyl radicals in the reaction. 70,71 The reaction can also be carried out using Boc-protected azetidine and piperidine (27)(28), which are important motifs in drug discovery.…”

“…21 Photocatalytic activation of organic halides is highly challenging because they have relatively negative reduction potentials (E red < −1.5 V vs. SCE), which require the use of strong reducing photocatalysts. [22][23][24][25][26] MOFs with a reduction potential generally positive than −1.0 V vs. SCE display a large redox mismatch for the direct PET activation of organic halides, thus blocking their further photocatalytic application starting from organic halides. 8,[27][28][29] Very recently, Leonori and coworkers reported a smart strategy to achieve the activation of halides using a homogeneous dye via the halogen-atom transfer (XAT) mechanism.…”

Photocatalyst-free visible light driven synthesis of gem-dihaloenones from alkynes, tetrahalomethanes and water

“…Visible light-mediated organic synthesis has become a powerful tool in organic synthesis due to its mild conditions, environmental friendliness, and green environmental protection. 9 Several transition metal complexes such as Ir 10 and Ru 11 complexes and organic dyes 12 have already been applied as photocatalysts for this purpose. However, these compounds usually have limitations such as high price, specific toxicity grades, or residues, limiting industrial use and large-scale organics production via photocatalysis.…”