Direct synthesis of completely unsymmetrical triarylmethanes via Fe(III) salt‐mediated in situ o‐quinone methides process

Abstract

An efficient and straightforward synthetic approach to completely unsymmetrical triarylmethanes through the situ-generated o-quinone methides from readily available starting materials has been successfully developed. In the presence of an Fe(III) salt, three different aromatic rings, including salicylaldehydes, arylboronic acids, and arenes, were incorporated into one molecule in a single step under the base/ligand-free conditions. The related reactions show high chemoselectivity and afford a variety of completely unsymmetrical triarylmethane products in good to excellent yields.

Development of Transition‐Metal‐Free Lewis Acid‐Initiated Double Arylation of Aldehyde: A Facile Approach Towards the Total Synthesis of Anti‐Breast‐Cancer Agent

“…[11] A synthetic approach to completely unsymmetrical triarylmethanes through the in-situ generated o-quinone methides has been successfully developed in the presence of an Fe (III) salt by Xu group (Scheme 1). [12] Crudden and co-workers reported a Pd-catalyzed sequential arylation of methyl phenyl sulfones (Scheme 1). [13] In 2011, Siegel and coworkers demonstrated a silylium ion initiated Friedel-Craft coupling of fluoroarenes to synthesize polycyclic aromatic fused hydrocarbons (Scheme 1).…”