Amine-Triggered Highly Facile Oxidative Benzannulation Reaction for the Synthesis of Anthranilates under Solvent-Free Calcium(II) Catalysis.

An amine-triggered facile synthetic approach of anthranilates has been described through benzannulation of readily available chemicals under one-pot solvent-free conditions using Ca(OTf) as the sustainable catalyst. In this regioselective approach, we described a reasonably longer cascade, which proceeds through β-enamino ester formation/Michael addition/intramolecular aldol reaction/elimination/aromatization/oxidative debenzylation/lactonization with a broad substrate scope and high yields. The isolation of intermediates authenticated the mechanism, and the synthetic utility of the products was also demonstrated.