Total Syntheses of Aflavazole and 14-Hydroxyaflavinine

Abstract

The first total syntheses of aflavazole (6) and 14-hydroxyaflavinine (8), two sterically congested indole diterpenoids, were accomplished. AlI₃-promoted alkyne Prins cyclization was exploited to construct their key structural motifs. An electrocyclization-aromatization sequence assembled the pentasubstituted arene of 6, and a Stille-Migita coupling furnished the tetrasubstituted olefin of 8. The benzylic and allylic C-O bonds were reductively cleaved at the late stage of the syntheses, respectively.