Intramolecular metal-free oxidative aryl-aryl coupling: an unusual hypervalent-iodine-mediated rearrangement of 2-substituted N-phenylbenzamides

Abstract

Hypervalent-iodine-mediated oxidative coupling of the two aryl groups in either 2-acylamino-N-phenyl-benzamides or 2-hydroxy-N-phenylbenzamides, with concomitant insertion of the ortho-substituted N or O atom into the tether, has been described for the first time. This unusual metal-free rearrangement reaction involves an oxidative C(sp(2))-C(sp(2)) aryl-aryl bond formation, cleavage of a C(sp(2))-C(O) bond, and a lactamization/lactonization. Furthermore, unsymmetrical diaryl compounds can be easily obtained by removing the tether within the cyclized product.

Keywords: cross-coupling; heterocycles; hypervalent iodine reagents; rearrangement.