Synthesis of Tribenzo[<i>b</i>,<i>d</i>,<i>f</i>]azepines via Cascade π-Extended Decarboxylative Annulation Involving Cyclic Diaryliodonium Salts

Abstract

Various functionalized tribenzo[<i>b,d,f</i>]azepines were prepared efficiently with the readily available 2-aminobenzoic acids and cyclic hypervalent diaryliodonium reagents as starting materials under Pd(II) catalysis. The key of this step-economical protocol is that the carboxylic acid functionality was employed as both a traceless directing group for the N-H activation/arylation and a functional handle for the tandem π-extended decarboxylative annulation.