# Controllable copper-catalysed photo-induced carbonylative cyclization to access dihydroquinolinones and oxindoles

## TL;DR

A new copper-catalyzed method uses visible light to efficiently create important chemical structures called oxindoles and dihydroquinolinones.

## Contribution

A mild, controllable method for synthesizing oxindoles and dihydroquinolinones using copper and visible light.

## Key findings

- The method works under mild conditions without expensive photocatalysts.
- Regioselective acyl radical addition is achieved by tuning alkene substitution patterns.
- The approach shows broad functional-group tolerance and enables late-stage molecule functionalization.

## Abstract

Oxindoles and dihydroquinolinones are pivotal heterocyclic scaffolds in medicinal and synthetic chemistry. Herein, we describe a controllable visible-light-induced, copper-catalyzed carbonylative cyclization of arylthianthrenium salts with alkenes, enabling the efficient synthesis of structurally diverse oxindoles and dihydroquinolinones. Notably, this transformation proceeds under mild conditions without the need for expensive photocatalysts, and regioselective acyl radical addition is achieved simply by tuning the substitution pattern of the alkene, which enables the switchable synthesis of carbonylated five- and six-membered heterocycles. Mechanistic studies indicate that blue-light irradiation promotes the copper-mediated reduction of arylthianthrenium salts, generating aryl radicals that subsequently capture CO to afford acyl radicals and initiate a tandem cyclization sequence. This method exhibits broad functional-group tolerance and offers a versatile platform for the late-stage functionalization of bioactive molecules.

A controllable visible-light-induced, copper-catalyzed carbonylative cyclization of arylthianthrenium salts with alkenes, enabling the efficient synthesis of structurally diverse oxindoles and dihydroquinolinones has been developed.