Application of a novel carbonyl ene reaction: Total syntheses of phyllanthocin and chlorovulone II

We describe the total syntheses of $(\pm)$-phyllanthocin (1), the aglycon of the potent antineoplastic agent phyllanthoside (2a), and of $(\pm)$-chlorovulone II (3), a halogenated marine prostanoid with high antiproliferative and cytotoxic activity.* The key step of both syntheses is a novel carbonyl ene reaction, which occurs between ordinary aldehydes and vinyl ethers that display the oxygen functionality at the central carbon of an allylic system, e.g., 2-methoxypropene, under the catalytic influence of 0.5 mol% of the 1:1 complex of Yb(fod)$\sb3$ and acetic acid (Figure I).* ftn*Please refer to dissertation for diagrams