2,7-Dinitrophenanthrene-9,10-dione as a photosensitizer for the dehydrogenative lactonization of 2-arylbenzoic acids

Abstract

This report describes the visible-light-induced C–H/COO–H oxidative coupling reaction of 2-arylbenzoic acids by using 2,7-dinitrophenanthrene-9,10-dione (DNPO) as a photocatalyst. The DNPO photocatalyst can be prepared on a large scale and exhibits excellent photo- and electrochemical properties, including a long excited-state lifetime (5.8 μs), high excited-state reduction potential ([E_redDNPO*/DNPO˙⁻] = +2.13 V vs. SCE), and good reduction stability. Mild reaction conditions, experimental simplicity, good atomic economy, and broad substrate scope are the features of the method described herein.