Cyanthiwigins B, F, and G
Total Syntheses of Cyanthiwigins B, F, and G
Stoltz et. al., Chem. Eur. J., 2011, Early View; [PDF] [SI] [GROUP]
I briefly contemplated not covering this, as I covered the Stoltz group conquest of liphagal last month,[1] and this uses the same palladium-catalysed enantioselective decarboxylative alkylation as the key asymmetry creating step. However, this is such a clever and powerful demonstration of the methodology that I couldn't help myself.[2] This time the targets are the cyanthiwigins, a family of marine diterpenoids with over 30 members, all sharing a highly conserved 5-6-7 tricyclic core. The few members isolated in sufficient quantity for testing, and the cyathanes in general, have demonstrated a range of biological activities so new routes to these compounds could be useful.
(+)-Liphagal
The Catalytic Enantioselective Total Synthesis of (+)-Liphagal
Stoltz et al., Angew. Chem. Int. Ed., 2011, Early View; [PDF] [SI] [GROUP HOMEPAGE]
This tetracyclic meroterpene has had quite a bit of attention from the synthetic community since its isolation back in 2006 from a Caribbean sponge. Along with other well known natural products such as resveratrol, staurosporine, and wortmannin it's an inhibitor of phosphatidylinositol 3-kinase (PI3K), an enzyme involved in numerous diseases. The fact that those all have wikipedia pages is quite telling. It's also got some cytotoxicity towards various cancer cell lines, but I suspect the reason people keep making it is the unique and interesting 6-7-5-6 ring system.