A simple ketone as an efficient metal-free catalyst for visible-light-mediated Diels–Alder and aza-Diels–Alder reactions

Abstract

Diels–Alder reactions are highly effective between electron-rich dienes and electron-poor dienophiles. However, these reactions with electron-rich dienophiles are limited and require forcing conditions. Based on this, an efficient metal-free homogeneous system has been developed for the Diels–Alder reactions between electron-rich dienophiles and dienes under visible-light conditions. Additionally, this catalyst has shown excellent reactivity for aza-Diels–Alder reactions. This simple catalyst is commercially available, non-toxic, and cheap and has shown excellent reactivity which is comparable to and in some cases even better than the reported metal-based catalysts. Finally, the mechanism of this reaction has been proposed based on the experimental evidence.