Substitution controlled aryne insertion: synthesis of diarylmethane/chromones.

Aryne insertion reaction with 2-aroyl malonates/cyanoesters lead to the formation of diarylmethane or chromones depending on the substitution on the aryne ring. The presence of an electronegative atom at the position of arynes generates chromones, whereas other arynes lead to the formation of diarylmethanes, a cascade double aryne insertion.

Synthesis of 2-Amino-2'-hydroxy-1,1'-biaryls via Cascade Benzannulation and C-N Bond Cleavage Sequence.

A serendipitous synthesis of N-substituted 2-amino-2'-hydroxy-1,1'-biaryls through an aryne annulation with indolyl β-ketonitrile/ester in a cascade manner is demonstrated. The reaction sequence involves benzyne-mediated [2 + 2] Stoltz-type cycloaddition-cleavage and intramolecular Michael addition followed by C-N bond cleavage under transition-metal-free reaction conditions. Interestingly, while [4 + 2] Diels-Alder reaction is a possible pathway, no traces of the regioisomer was isolated.