Comprehensive Review on Metal Nanoparticles Catalyzed Synthesis of Aza- and Oxa-Heterocycles Reported in 2021

Among the several heterocyclic compounds, nitrogen and oxygen are predominant heterocycles due to their abundant biological importance. The nanoparticles have demonstrated the excellent catalytic activity under optimum conditions with higher reusability or recyclability and higher yields of synthetic heterocyclic targets. Previously we reviewed the synthesis of aza- and oxa-heterocycles catalyzed by metal nanoparticles (MNPs) in 2009-2019 and published an update of such reports of 2020 on the same subject. With anticipations to the next, the present comprehensive work highlights the synthesis of aza- and oxa-heterocycles catalyzed by MNPs reported during the year, 2021 to update the reader of the present work with the most recent trends in selection of MNPs in the synthesis of desired heterocyclic scaffolds.