| The naturally occurring antibiotic polyquinane, hypnophilin, has attracted synthetic chemists for a number of years due to its reputed antibacterial and antitumor properties. As a highly oxygenated linear triquinane containing six stereocenters, hypnophilin was a suitable target for application of our squarate ester cascade reaction. The success of constructing 72 via a squarate ester cascade reaction allowed us to synthesize hypnophilin in a short route.; Two 2-cyclopentenones 137 and 138 were prepared by a convergent pathway involving the coupling of cyclopentenyl bromide 139 and racemic ketone 150 followed by desilylation, perruthenate oxidation, and ring-closing metathesis. New photorearrangements were discovered when 137 and 138 were irradiated through quartz.; Convergent pathways for synthesizing building blocks A and B for pectenotoxin II were investigated. Advanced precursor 238 was prepared involving the coupling of iodide 184 and Weinreb amide 185 followed by removal of the two PMB ethers, hydrogenolysis, DMP oxidation, Wittig reaction, reduction, Sharpless' asymmetric epoxidation, DMP oxidation, and Wittig reaction. Four more functional group transformations would be needed to construct building block A. Advanced precursor tetrahydrofuran 283 was prepared involving a Julia olefination via the coupling of sulfone 277 and aldehyde 243 followed by a series of chemical operations including Sharpless' asymmetric dihydroxylation. After eight more chemical operations, building block B could be synthesized. |
