Erratum: Organophotoredox-Catalyzed Intermolecular Oxa-[4+2] Cycloaddition Reactions (The Journal of Organic Chemistry (2019) 84:17 (10669?10678) DOI: 10.1021/acs.joc.9b01156)

When we reinvestigated the Stern-Volmer experiment of the TXT photocatalyst, we found our previous measurement related to the concentration of 4-methoxystyrene (see Figure 1 in original article) is in error. In a typical experiment, the emission spectrum of a 1 × 10-4 M solution of TXT in CH3CN was collected. Then, the appropriate amount of 4-methoxystyrene (0.05M) was added to the measured solution, and the emission spectrum of the sample was collected. On the other hand, the ortho-quinone methide 1a was not correctly measured by the same manner because the ortho-quinone methide 1a is solid, and it is difficult to exactly weigh 1a due to its very small amount. Therefore, we examined another method below.