Synthesis of aromatic natural product frameworks using enyne metathesis

Enynes, easily obtained by the Sonogashira coupling reactions of aromatic iodides, undergo, with good yields, enyne metathesis using the Grubbs catalyst. The resulting dienes are interesting carbo- and heterocycles which can give complex natural frameworks by Diels–Alder reactions. Thus, an estradiol type skeleton is obtained in two steps from the corresponding enynes. An example of a metathesis-Diels–Alder cascade one-pot process is reported.