Photoinduced Halogen Bond Assisted Biaryl Synthesis via 1,4-Aryl Migration
Vijay Kumar Simhadri1, Akash Bisoyi1, Rupam Sur1
1School of Chemistry, Indian Institute of Science Education and Research, Thiruvananthapuram 695551, India.
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In this work, we report a photoinduced, halogen-bond-assisted, catalyst-free strategy for the synthesis of a broad range of biaryl compounds. The halogen-bonding interaction facilitates the generation of an aryl radical from N-aryl-2-iodobenzamides and N-sulfonyl-2-iodobenzamides, which subsequently undergoes a 1,4-aryl migration through a Truce-Smiles-type rearrangement, ultimately affording structurally diverse and valuable functionalized biaryls. Preliminary mechanistic investigations using TEMPO trapping and EPR spectroscopy support the involvement of radical intermediates, while additional studies (UV-vis and NMR) confirm the presence of a halogen-bonding interaction between the amine and the aryl iodide. Moreover, DFT calculations elucidate the preference for ipso substitution over ortho addition and provide insight into the overall reaction pathway.
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