Diastereoselective Total Synthesis of (±)-Basiliolide B and (±)-<i>epi</i>-8-Basiliolide B

The C8 and C9 stereogenic centers of the basiliolide/transtaganolide family have been established stereoselectively using a cyclopropane ring-opening strategy, which has been studied by DFT calculations of a variety of lithium-chelating models. The highly functionalized intermediates obtained in this strategy were successfully employed for the diastereoselective total synthesis of (±)-basiliolide B and (±)-<i>epi</i>-8-basiliolide B. The decalin core with a lactone bridge was constructed via a 2-pyrone Diels–Alder (DA) cycloaddition, and the unprecedented seven-membered acyl ketene acetal was established by a biomimetic intramolecular <i>O</i>-acylation cyclization