Expedient Diels-Alder cycloadditions with ortho-quinodimethanes in a high temperature/pressure flow reactor

We describe herein Diels-Alder cycloadditions enabled by the efficient ring-opening of benzocyclobutenes and benzothiophene-2,2-dioxides using a high temperature/pressure flow reactor. The resultant ortho-quinodimethanes were generated and subsequently reacted with a wide range of dienophiles to provide complex heterocyclic ring systems. The use of flow technology allowed these reactions to be completed within minutes using conventional, readily removed solvents.