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

## TL;DR

This paper presents a new and efficient method to synthesize Decumbenine B analogues using C–H functionalization, which also enables the creation of fluorescent molecules with useful sensing properties.

## Contribution

A regioselective C–H functionalization method using Ru/Pd/Cu catalysts for Decumbenine B analogues with photophysical applications.

## Key findings

- Pd(ii) and Cu(ii) prefer halogenation and selenation of the isoquinoline precursor.
- Ru(ii) effectively catalyzes hydroxymethylation of the same precursor.
- The method produces fluorescent molecules with aggregation-induced emission and toxic compound sensing.

## 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.

A regioselective C–H functionalizations [–CH2OH, –Br/Cl and –SePh)] via Ru/Pd/Cu catalyst has been developed for the synthesis of Decumbenine B analogues. DFT studies for metal selection and toxic-compound sensing are attraction of this protocol.