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

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.

Constructions of tetrahydro-γ-carboline skeletons via intramolecular oxidative carbon-carbon bond formation of enamines.

The synthetically and biologically important 4-methyl and 4-methoxy tetrahydro-γ-carboline compounds were readily synthesized in high yields from an aryl amine and a 5-amino-3-oxopentanoate derivative through a series of reactions of enamination, oxidative annulation, deprotection/lactamization and the final reduction reaction of the carbonyl group. The underpinning strategy involves the oxidative C(sp(2))-C(sp(2)) bond formation realized by either Pd(OAc)2/Cu(OAc)2 or a hypervalent iodine reagent.