A Metal-Free Tandem Demethylenation/C(sp²)–H Cycloamination Process of <i>N</i>‑Benzyl-2-aminopyridines via C–C and C–N Bond Cleavage

A mild, metal-free synthesis of pyrido[1,2-<i>a</i>]benzimidazoles starting with <i>N</i>-benzyl-2-aminopyridines, which employs PhI(OPiv)₂ as a stoichiometric oxidant, has been developed. The process is initiated by an unusual PhI(OPiv)₂-mediated <i>ipso</i> S_EAr reaction, followed by solvent-assisted C–C and C–N bond cleavage

CuI-Mediated Sequential Iodination/Cycloetherification of <i>o</i>‑Arylphenols: Synthesis of 2- or 4‑Iododibenzofurans and Mechanistic Studies

An efficient synthesis of 2- or 4-iododibenzofurans through CuI-mediated sequential iodination/cycloetherification of two aromatic C–H bonds in <i>o</i>-arylphenols has been developed. Both the preexisting electron-withdrawing groups (NO₂, CN, and CHO) and the newly introduced iodide are readily modified for a focused dibenzofuran library synthesis. Mechanistic studies and DFT calculations suggest that a Cu(III)-mediated rate-limiting C–H activation step is involved in cycloetherification