Collective total syntheses of cytochalasans and merocytochalasans

Recent advances in the total synthesis of cytochalasan natural products using bioinspired strategies

“…It contains an unprecedented 13-oxatetracyclo [7.2.1.12.5.01.6] tride-8,12-dione core and as many as 20 stereogenic centers. In 2018, Tang's group 25 and Deng's group 26 independently completed the total synthesis of asperchalasine A at the same time through an intermolecular Diels–Alder cycloaddition, an acid-promoted Diels–Alder reaction and a [5 + 2] cycloaddition reaction (Schemes 10 and 11). Biogenetically, asperchalasine A ( 17 ) is comprised of two molecules of aspochalasin B ( 78 ) and one of epicoccine ( 129 ).…”

“…Tang and co-workers developed a unified approach toward aspochalasin B ( 78 ) through an intermolecular Diels–Alder reaction to forge the isoindolone bicyclic core and ring-closing metathesis (RCM) to form the 11-membered macrocycle. 25 Their synthesis commenced with the preparation of dienophile 111 . Acylation of lactam 40 , after deprotonation using 109 and t -BuLi with 4-pentenoyl chloride ( 110 ) followed by selenation and oxidative elimination, afforded 3-pyrrolin-2-one 111 smoothly.…”