Heterogeneous Rhodium‐Catalyzed Aerobic Oxidative Dehydrogenative Cross‐Coupling: Nonsymmetrical Biaryl Amines

Abstract

The first heterogeneously catalyzedo xidative dehydrogenative cross-coupling of aryl amines is reported herein. 2-Naphthylamine analogues were reacted with various electronrich arenes using ah eterogeneous Rh/C catalyst under mild aerobic conditions,t hus affording nonsymmetrical biaryl amines in excellent yields with high selectivities.T his reaction provides am ild, operationally simple,a nd efficient approach for the synthesis of biaryls which are important to pharmaceutical and materials chemistry.

Iron‐Catalyzed Oxidative C−C Cross‐Coupling Reaction of Tertiary Anilines with Hydroxyarenes by Using Air as Sole Oxidant**

“…Moreover, we wanted to avoid the need for a transient connection between the two reactants for cross‐coupling [21] . According to previous reports, [7, 13, 14, 22] we hypothesized that the homocoupling of anilines could be suppressed by substituents causing a steric hindrance at the amino group. Reaction of a radical cation generated by SET oxidation of a tertiary aniline with a sterically less hindered phenol should preferentially form a C−C bond either via radical or electrophilic aromatic substitution (Scheme 2).…”

“…Recently, Shindo and co‐workers described a heterogeneous Rh‐catalyzed aerobic oxidative cross‐coupling for the synthesis of unsymmetrical biaryl compounds (Scheme 1). [13] …”