Directing group-assisted C–H functionalization of 2-arylbenzo[f]isoquinoline: a robust route to decumbenine B analogues with photophysical applications

Abstract

An efficient transition metal-catalysed regioselective short synthetic route to Decumbenine B analogues is prepared from the green precursor 2-arylbenzo[f]isoquinoline (obtained via urea-promoted neat reaction). The single precursor capable of introducing –CH₂OH, –X(–Br/–Cl), –SePh groups via Ru/Pd/Cu-catalyzed C–H functionalization. Theoretical and experimental investigations confirmed that Pd(II) and Cu(II) preferentially interact with the isoquinoline precursor to drive halogenation and selenation, respectively, while Ru(II) effectively catalyzes the hydroxymethylation reaction. The protocol is extended to newly synthesized fluorescent molecules that exhibit aggregation-induced emission (AIE) and toxic compound sensing properties. Consequently, this approach assists us in accessing a diverse array of naturally occurring analogues and facilitates more efficient and effective biological studies with minimal effort.