Spirodiepoxide-based cascade strategies to the upper hemisphere of pectenotoxin-4

Disclosed are studies on allene oxidations and functionally diverse motif. The utilization of spirodiepoxide based methodologies in the synthesis of highly functionalized α-tetrahydrofuranyl-α'-hydroxy ketones led to a cascade strategy to the upper hemisphere of pectenotoxin-4. Remarkably, an advanced allene intermediate with six stereo centers and one epoxide was converted to a C1-C19 sector of pectenotoxin-4 with 9 stereo centers including 3 rings in one pot and 26% yield. It is also shown that electrophile capture with osmium enolates resulted in anti-α-halo-α’-hydroxyketone products. This method complements our spirodiepoxide chemistry in stereroselective conversion of chiral allenes. Finally, we envisioned that a cyclodecatrienone, prepared via C-C fragmentation of a cis-decalin derivative, could be built up to Vernonia allenes and other structurally related germacranes by taking advantage of our allene chemistry.Ph.D.Includes bibliographical referencesby Da X