Synthetic studies on the dienophile unit of methyl isosartortuoate. Part 2: SmI2-mediated 14-membered carbocyclization

The dienophile unit of methyl isosartortuoate has been synthesized. The 14-membered carbocycle was constructed by a SmI2-mediated intramolecular Reformatsky reaction. The introduction of the oxo group at the γ-position of the α,β-unsaturated ester was achieved by rearrangement of an β,γ-epoxy ester.