Methylene Blue as a Photosensitizer and Redox Agent: Synthesis of 5‐Hydroxy‐1<i>H</i>‐pyrrol‐2(5<i>H</i>)‐ones from Furans

Abstract

Abstract A highly efficient and general singlet‐oxygen‐initiated one‐pot transformation of readily accessible furans into 5‐hydroxy‐1 H ‐pyrrol‐2(5 H )‐ones has been developed. The methodology was extended to the synthesis of other high‐value α,β‐unsaturated γ‐lactams. This useful set of transformations relies not only on the photosensitizing ability of methylene blue, but also on its redox properties: properties that have until now been virtually ignored in a synthetic context.