We report the details of the total synthesis of natural and non-natural jatropha-5,12-dienes. The successful tactic for the assembly of the strained trans-bicyclo[10.3.0]pentadecane scaffold employed a B-alkyl Suzuki-Miyaura cross-coupling for the formation of the C5/C6 double bond and a ring-closing metathesis for the construction of the C12/C13 double bond. The key step of the synthesis of the cyclopentane fragment, an uncatalyzed intramolecular carbonyl-ene reaction, was studied computationally by DFT calculations. The members of the ensemble of synthetic natural and non-natural jatrophanes were subsequently examined as modulators for the ABCB1, ABCG2, and ABCC1 efflux proteins, which are associated with multidrug resistance in cancer chemotherapy.

The enantioselective total synthesis of the jatrophane diterpene (-)-15-O-acetyl-3-O-propionylcharaciol is described. Starting from an advanced cyclopentane building block, a B-alkyl Suzuki-Miyaura cross-coupling and carbonyl addition were utilized to assemble a fully functionalized triene, and a ring-closing metathesis was then employed to construct the rigid 12-membered ring. Twenty-five years after the original report on the isolation of the natural product, our total synthesis unambiguously corroborates the original tentative structural assignment.

Results from efforts aimed at the synthesis of polyhydroxylated jatropha-5,12-dienes are unveiled. An apparently pre-qualified plot consisting of successive aldol addition and ring-closing metathesis was pursued in order to construct the fully oxidized trans-bicyclo[10.3.0]pentadecane scaffold of naturally occurring jatrophanoids.