A series of structurally simplified cryptocaryone analogues were synthesized by a facile Pd-catalyzed acetoxylation of alkyne-tethered cyclohexadienones and evaluated as inhibitors of NF-κB signaling. Compounds 10 and 11 were found to possess low micromolar inhibitory properties towards induced NF-κB activity by blocking p50/p65 nuclear protein through a covalent inhibition mechanism. Both compounds were able to inhibit NF-κB-induced IL-8 expression and exhibited antiproliferative activity against two model cancer cell lines. These analogues constitute a promising new scaffold for the development of novel NF-κB inhibitors and anticancer agents.

A full account of our synthetic work toward the first total synthesis of the neuroactive marine macrolide (-)-palmyrolide A is described. Our first-generation approach aimed to unlock the unknown C(5)-C(7) stereochemical relationship via the synthesis of four diastereomers of palmyrolide A aldehyde, a known degradation product. When these efforts provided inconclusive results, recourse to synthesizing all possible stereocombinations of the 15-membered macrolide was undertaken. These studies were critical in confirming the absolute stereochemistry, yielding the first total synthesis of (+)-ent-palmyrolide A. Subsequent to this work, the first protecting-group-free total synthesis of natural (-)-palmyrolide A is also reported.

The cyclization of 2,5-cyclohexadienones tethered to activated methylene groups was studied. The substitution around the cyclohexadienone ring serves to regioselectively direct these cyclizations based primarily on electronic effects. In the case of brominated substrates, these reactions proceed to give highly unusual electron-deficient tricyclic cyclopropanes. By using a Cinchona alkaloid-based phase-transfer catalyst, prochiral cyclohexadienones can be desymmetrized with moderate stereoselectivity.

Regioselective cyclizations of alkyne-tethered cyclohexadienones can be accomplished under palladium catalysis. The cyclization involves an initial Pd-mediated acetoxylation of the alkyne, followed by migratory insertion and protonolysis of the resulting palladium enolate. The predictable regioselectivity of these atom-economical and stereoselective reactions is influenced by developing steric interactions during migratory insertion of a vinyl palladium intermediate.

The absolute stereochemistry of the cystargolides was determined by total synthesis. Evaluation of synthetic cystargolides and derivatives showed that the natural (2S,3R) stereochemistry is essential for activity. Moreover, benzyl esters (−)-10 and (−)-15 were found to be about 100 times more potent, and to selectively kill MCF-7 cancerous cells.