Metal Free Synthesis of Carbazoles by Photostimulated Reactions of 2'- Halo-[1,1'-biphenyl]-2-amines

WALTER D. GUERRA; R. A. ROSSI; ADRIANA B. PIERINI; SILVIA M. BAROLO

JOURNAL OF ORGANIC CHEMISTRY

AMER CHEMICAL SOC

Lugar: Washington; Año: 2015 vol. 80 p. 928 - 941

0022-3263

An efficient and simple protocol for the preparation of a series of 9H-carbazoles by photostimulated SRN1 substitution reactions is presented. Substituted 9H-carbazoles were synthesized with moderate to excellent yields (up to 96%) through an intramolecular C-N bond formation of 2´-halo-[1,1´-biphenyl]-2-amines by the photoinitiated SRN1 mechanism under mild and ?metal-free? conditions. The biphenyl amines used as substrates were obtained with moderate to very good isolated yields (21-84%) by two approaches: A)the cross-coupling Suzuki-Miyaura reaction, and B) the radical arylation of anilines. Some key aspects of the proposed mechanism were evaluated at the B3LYP/6-311+G* level.