Total synthesis of (−)-phaeosphaeride B by a biomimetic conversion from (−)-phaeosphaeride A

Abstract We have accomplished the first total synthesis of STAT3 inhibitory (−)-phaeosphaeride A and its stereoisomer (−)-phaeosphaeride B. This work confirms the configurational assignment of these natural products. Notably, TFA-mediated dehydrative stereoinversion of phaeosphaeride A afforded phaeosphaeride B, based on our hypothesis of the biosynthesis mechanism of phaeosphaeride B from phaeosphaeride A.