A Unified Bioinspired “Aplysinopsin Cascade”: Total Synthesis of (±)-Tubastrindole B and Related Biosynthetic Congeners

Applying a biomimetic approach, the first total synthesis of (±)-tubastrindole B is reported herein. This work features a ring-expansion cascade of a dictazole-type precursor into cycloaplysinopsin-type congeners. Moreover, the isolation of a transient biogenetic intermediate represents a milestone in the biosynthetic understanding of this family of marine alkaloids.