Synthesis of Selaginpulvilin D by [2 + 2 + 2] Cyclotrimerization─A Second-Generation Approach

We report a second-generation synthesis of selaginpulvilin D that addresses key limitations of our earlier route. An efficient early-stage [2 + 2 + 2] cyclotrimerization now provides high-yield access to the molecule's fluorene core. Previously, this step was low-yielding and relied on a difficult-to-prepare aryldiyne intermediate. By introducing the arylalkyne moiety after the cyclotrimerization, the new strategy removes these issues and delivers a more practical, efficient, and modular pathway to selaginpulvilin D.