Palladium-Catalyzed Dual Coupling Reaction of 2-Iodobiphenyls with o-Bromoanilines through C–H Activation: An Approach for the Synthesis of Tribenzo[b,d,f]azepines

Abstract

A novel and straightforward approach for the synthesis of tribenzo­[b,d,f]­azepines starting from 2-iodobiphenyls and 2-bromoanilines has been developed. A wide range of tribenzo­[b,d,f]­azepines were obtained in good to excellent yields via a cascade intermolecular palladium-catalyzed C–H activation/dual coupling reaction. C,C-palladacycles, which are generated by C–H activation of 2-iodobiphenyls, should be the reaction intermediates.

Ullmann‐Goldberg and Buchwald‐Hartwig C−N Cross Couplings: Synthetic Methods to Pharmaceutically Potential N‐Heterocycles

“…For the scope of the biphenyl 86, multiply substituted biphenyls were tested and the result showed that strong electron-donating groups like OMe on the para position of both rings increase the efficacy. [85]…”

“…The presence of Me on the amine group of aniline in 87 did not affect the reaction negatively, but the presence of Ph group in the same position reduced the yield dramatically. For the scope of the biphenyl 86 , multiply substituted biphenyls were tested and the result showed that strong electron‐donating groups like OMe on the para position of both rings increase the efficacy [85] …”

Synthesis of Tribenzo[b,d,f]azepines via Palladium-Catalyzed Annulation Reaction of 2-Iodobiphenyls with 2-Halogenoanilines

“…On the basis of the experimental results and previous reports, − a possible reaction mechanism was proposed in Scheme . Initially, the oxidative addition of 2-iodobiphenyls 1 to Pd(0) generates Pd­(II) intermediates A .…”

“…A variety of substituted tribenzo­[ b , d , f ]­azepines can be synthesized according to this method (Scheme C). During the preparation of this manuscript, a similar work was reported by Zhang’s group …”

Construction of aziridine, azetidine, indole and quinoline-like heterocycles via Pd-mediated C–H activation/annulation strategies

“…Recently, a Pd-catalysed dual coupling of 2-iodobiphenyls and 2-bromoanilianes furnishing tribenzo [b,d,f]azepines was reported by Zhang and colleagues. 79 In the presence of 5 mol% Pd(OAc) 2 , phosphine ligand and Cs 2 CO 3 , 24 azepines, they were synthesized in good to excellent yields. This transformation featured the sequential C-C and C-N bond forming through the C-H activation process (Scheme 50).…”