Traceless synthetic approach towards oxaza-dicyclopenta[a,h]naphthalenes under solvent-free condition: a basic alumina-supported green protocol

A novel class of oxaza-dicyclopenta[a,h]naphthalenes was efficiently constructed from furo[3,2-h]quinoliniums through a 1,3-dipolar cycloaddition reaction employing basic alumina as the solid support. The distinguished features of this methodology encompass high yield, minimal reaction time, operational simplicity and general applicability coupled with structural novelty of the products. The intermediate furo[3,2-h]quinoliniums were easily derived through a two-step methodology, namely a tandem Sonogashira–alkynylation–cyclization, followed by quaternization of the furo[3,2-h]quinoline scaffold.