Catalytic and Aerobic Oxidative Biaryl Coupling of Anilines Using a Recyclable Heterogeneous Catalyst for Synthesis of Benzidines and Bicarbazoles.

In this study, a heterogeneous rhodium-catalyzed oxidative homocoupling reaction of anilines utilizing molecular oxygen as the sole oxidant is reported. Employing a commercially available and recyclable Rh/C catalyst enabled the oxidative dimerization of various anilines, including ,-disubstituted and -monosubstituted anilines, as well as diarylamines, triarylamines, and carbazoles. Additionally, the catalytic protocol was extended to the ortho-ortho coupling of anilines, affording 2,2'-diaminobiphenyls with high regioselectivity.

Aerobic C-H Oxidation of Arenes Using a Recyclable, Heterogeneous Rhodium Catalyst.

A novel, practical protocol for the aerobic direct C-H acetoxylation of arenes, employing a recyclable heterogeneous rhodium catalyst, is reported herein. The trifluoroacetoxylation of 2-amido-substituted anthracenes proceeded at the 9-position with exclusive regioselectivity. The oxidation of variously substituted anthracenes and other polycyclic aromatics with molecular oxygen as a terminal oxidant proceeded under mild conditions, providing products in good to excellent yields.

Aerobic oxidative homocoupling of aryl amines using heterogeneous rhodium catalysts.

The first heterogeneous catalyzed oxidative coupling of aryl amines is reported. Aryl amines were dimerized at room temperature under air using a heterogeneous Rh/C catalyst in the presence of acids. By choosing a suitable acidic solvent, biaryl compounds and carbazoles were selectively prepared in good yields.