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)2 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.