Transformation of Renieramycin M into Renieramycins T and S by Intramolecular Photoredox Reaction of 7‑Methoxy-6-methyl-1,2,3,4-tetrahydroisoquinoline-5,8-dione Derivatives

In connection with our studies of biologically active 1,2,3,4-tetrahydroisoquinoline marine natural products, we describe herein a useful intramolecular photoredox transformation of 7-methoxy-6-methyl-1,2,3,4-tetrahydroisoquinoline-5,8-dione tricyclic models into 5-hydroxy-tetrahydroisoquinol­[1,3]­dioxoles in excellent yields. We applied this methodology to the transformation of renieramycin M into renieramycins T and S and the transformation of saframycin A. The results of cytotoxicity studies are also presented.