Synthesis of natural polyacetylenes bearing furan rings.

The first total syntheses of four new polyacetylene compounds have been achieved using convergent routes, which involved Cadiot--Chodkiewicz copper-catalyzed cross-coupling reactions to sp-sp centers as the key steps. 19-Furan-2-ylnonadeca-5,7-diynoic acid (1), 19-furan-2-ylnonadeca-5,7-diynoic acid methyl ester (2), 2-pentacosa-7,9-diynylfuran (3), and 21-furan-2-ylhenicosa-14,16-diyn-1-ol (4) were stable and could be readily identified, isolated, and purified in high overall yields.