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

W. D. GUERRA; R. A. ROSSI.; A. B. PIERINI; S. M. BAROLO

JOURNAL OF ORGANIC CHEMISTRY

AMER CHEMICAL SOC

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

0022-3263

ABSTRACT: An efficient and simple protocol for the preparation of a series of 9Hcarbazolesby photostimulated SRN1 substitution reactions is presented. Substituted9H-carbazoles were synthesized in low to excellent yields (up to 96%) through anintramolecular C−N bond formation of 2′-halo[1,1′-biphenyl]-2-amines by thephotoinitiated SRN1 mechanism under mild and ?transition-metal-free? conditions.The biphenylamines used as substrates were obtained with isolated yields rangingfrom 21% to 84% by two approaches: (A) the cross-coupling Suzuki−Miyaurareaction and (B) the radical arylation of anilines. Some key aspects of the proposedmechanism were evaluated at the B3LYP/6-311+G* level.