Synthesis of 6,12-Epiminodibenzo[<i>b</i>,<i>f</i>][1,5]diazocines via an Ytterbium Triflate-Catalyzed, AB₂ Three-Component Reaction

Abstract

An efficient and selective procedure for the synthesis of epiminodibenzo[b,f][1,5]diazocines involving a AB₂ three-component reaction is developed. Two equivalents of suitably substituted 2-aminoarylaldehydes reacted with arylamines in the presence of Yb(OTf)₃ to afford the desired products in high yields. The reaction is highly atom-economic and waste-free, in addition to allowing the generation of two heterocyclic rings and four C-N bonds in a single operation. Significantly, this approach is complementary to the existing literature procedures, affording arylamine-derived products that could not be accessed previously. A plausible mechanism is proposed involving an imine formation-intermolecular annulation-intramolecular iminium ion cyclization sequence.