Coupling of Alkenes and Alkynes: Synthesis of the C1−C11 and C18−C28 Fragments of Miyakolide

2008-05-15T00:00:00Z (GMT) by Barry M. Trost Brandon L. Ashfeld
A transition metal-mediated, atom-economical approach toward the crucial A and D rings of miyakolide is described. A Pd-catalyzed alkyne−alkyne coupling/6-<i>endo</i>-<i>dig</i> cyclization is employed to assemble the A ring fragment. The key D ring pyran is constructed utilizing an Ru-catalyzed alkene−alkyne coupling followed by a Pd-catalyzed allylic alkylation to establish the all-cis stereochemistry.