Total Syntheses of Proposed Structures of 4,10-Dihydroxy-8,12-guaianolides

Thefirst total syntheses of two 4,10-dihydroxy-8,12-guaianolides that were reported to be natural products wereachieved. Toward the syntheses of a collection of relatedguaianolides, the typical 5,7-fused system of 8,12-guaianolideswas constructed by a ring expansion reaction of a hydroxylatedcoronafacic acid analogue that can be practically synthesized andoptically resolved. The total syntheses of these compoundsrevealed that the previously reported structures of both natural products were incorrect.

Automated summary

The total syntheses of two natural products, 4,10-dihydroxy-8,12-guaianolides, were achieved. The construction of the typical 5,7-fused system of 8,12-guaianolides using a ring expansion reaction revealed that the previously reported structures of both natural products were incorrect.