I now realize that that is actually 4 compounds. none have i found synthesis of yet.

The only people I know of who have attempted the synthesis of these compounds are; Lothar Bore, Tadashi Honda and Gordon Gribble. J. Org Chem, 2000, 65(19) pp 6278-6282. You could try finding out if they are still active in research and where they are based and contact them directly for advice if the above reference is not suitable to your needs. Failing that, as you have hinted in your question, most of the accessible journal articles deal with the extraction, isolation and medical effects of these pentaterpenes. I suspect that neither the synthesis or the extraction and purification are particularly straight forward.