Oxidative Aryl-Coupling Reactions in Synthesis

Abstract

The oxidant-mediated coupling of electron-rich arene rings has served over several decades as a valuable procedure to access biaryl units. The complex mixtures of isomers that often plagued the earliest studies have gradually given way to synthetically useful product distributions upon application of more selective coupling protocols. Continual advances in the nature of the oxidant (and its attendant ligands) and more precisely defined reaction conditions have led to increasing levels of control upon CaC bond formation. Chemoselective (CaC vs. CaO bond formation with phenols; suppression of product oxidation), regioselective (o-o0, vs. o-p0 vs. p-p0 CaC bond formation), and, more recently, s..