Ortho Arylation of N-Aryl Amides and the Construction of Diagonal Tetraaryldiamines and N-Doped Picenes via BBr3-Derived Dibromoboracycles

31 May 2024, Version 2
This content is a preprint and has not undergone peer review at the time of posting.

Abstract

The synthesis of biaryl amides, which are prevalent motifs in bioactive molecules, often necessitates lengthy and inef-ficient procedures. To address these limitations, catalytic C-H activation protocols have emerged, enabling the direct ortho-arylation of aryl amides. However, these protocols often suffer from issues such as lack of selectivity, reliance on stoichiometric oxidants, and the requirement for excess reagents and harsh reaction conditions. To overcome these challenges, we present a novel and highly selective protocol for the ortho-arylation of N-aryl amides and ureas. The high selectivity originates from the directed installation of BBr3 to form a boracycle, which then undergoes cross-coupling with an aryl halide. Our method offers significant advantages, including mild reaction conditions, excellent site-specificity, and scalability. The protocol demonstrates broad compatibility with a diverse range of readily accessi-ble functionalized anilides and aryl iodides, as evidenced by 55 successful examples yielding products in the 30–95% range. Furthermore, our methodology surpasses conventional approaches by facilitating the one-pot selective diagonal diarylation of dianilides. This capability unlocks the construction of previously unattainable diagonal aryl systems, which serve as valuable precursors for the synthesis of diagonal tetraaryldiamines and N-doped picenes, two crucial compound classes in materials science

Keywords

Boron
C-H activation
cross-coupling
Suzuki-Miyayra
Palladium
BBr3

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